Thursday, December 25, 2008

Noise Reduction in Elements

Let's discuss the two most likely sources of noise we are likely to encounter.

HIGH ISO NOISE

When we went and set the ISO to 3200, we knew we were in trouble. We went there because we had no choice. Given the poor light, we couldn't possibly hope to get a high enough shutter speed or a small enough aperture to freeze the action, compensate for the telephoto shake, get all parts of the room in focus etc etc. We knew that we were going to have to accept some compromises with noise in order to get the shot but there was something ABOUT the pic which was more important than the potential noise problem. If we went to the trouble of hiking up the ISO, we will probably feel that the image is important enough for some heroic efforts towards optimisation.

UNDEREXPOSURE

Even at civilised ISO settings, we can still get into noise trouble. Often we find ourselves having underexposed a relatively important image on a paying shoot which then has to have substantial mid-tone boosting - a perfect recipe for noise. If I have bracketted or gotten other, better exposed versions of the same subject I'll discard the pic in question but sometimes Sod's Law applies and it's all I've got. I then have to try to do something acceptable with it.

In either situation, we are going to have to accept that the noisy image will never be the impeccably smooth and colour precise object of beauty it MAY have been at low ISO settings and/or if we'd have exposed the thing correctly. What then are we to do?

  • We can accept the noise as it is.
  • We can make the noise seem more acceptable.
  • We can try to reduce the noise.
  • We can try to eliminate the noise
There are times when the actual picture and a reasonable degree of detail will be all important in which case we may need to leave the noise alone. There are times when the subject of the picture is very important but small detail is not the essence, in which case we can risk smearing small detail so long as the principle features of the image remain clear and defined. There are times when some form of film grain style noise might prove more acceptable or actually assist the image. Here we might remove colour noise and/or reduce colour saturation - perhaps render the image in greyscale. Sometimes we can compromise, particulary for smallish prints - remove SOME noise but accept the fact that some must be allowed to remain. There are times when smoothness and softness is the most appropriate look and loss of fine detail can be "lived with". In this case we can go further with noise reduction. Each of us must decide, in the case of every new noisy image, which is the best approach.

Certainly our decision making will be influenced by the ultimate display application. If the image will finish up as a small print or a relatively small image on a website, we enjoy a little more latitude than if it is to be published in the print media or blown up for framing. Likewise, depending on its subject value, a news pic will sometimes be acceptable in grainy greyscale but a commercial image in a display ad must be as technically perfect as possible.

Let's get one thing straight. With very few exceptions, noisy, high ISO images will RARELY be converted to clean, sharp, high detail images with one, simple, carefree pass of the NR software. It never really works that way. When we set out to remove noise artifacts, inevitably some details and texture will be interpretted as noise and get removed as part of the deal. In the final analysis, we WILL have to accept one or other of the above compromises ..... albeit, only after a good fight. For the purpose of THIS exercise let us decide to reduce noise to roughly acceptable levels - suitable for small prints and medium sized website illustrations

Until recently running "Noise Ninja" or "Neat Image" as a plug-in was the way to go. In recent times Photoshop and Elements have had the benefit of a serviceable noise reduction facility of their own in the form of Filter - Noise - Reduce Noise. Neat Image & co. are more powerful but with the judicious use of Layers and multiple passes on selected areas it can do pretty well.

Here is an approach upon which you may like to base your own experiments:

  1. Go to Layers menu and click on Duplicate Layer
  2. Go to Filter - Noise - Reduce Noise. Strength 10, Preserve Details 20% and Reduce Colour Noise 70% Click OK
  3. Choose shadow areas and expanses of featureless open space (e.g. sky & walls) which continue to show noise, select them roughly with the Quick Selection tool. Re-run Reduce Noise on the selected areas with the previous settings.
  4. Tour the image, viewing it at 1:1 (100%) and using the "Blur Tool", tidy up any last remaining spots of noticeable noise or processing artifacts
  5. Run the Unsharp Mask. Amount 200, Radius 1, Threshold 10
  6. Using the Opacity slider, fine tune the blending of the treated and untreated layers
  7. Save as a .psd file. Flatten image and save as a jpeg.

See my work at http://www.pbase.com/davidhobbs

Wednesday, December 24, 2008

Sharpening Alternatives in Elements

It is my firm belief that the Unsharp Mask remains the most satisfactory approach to sharpening in the Adobe Photoshop Elements. The tool in Elements is virtually identical to the one in CS4. There are masses of references, advice sites, tutorials, opinions etc based on this one tool. If used in combination with Layers and or tools like the great new "Quick Selection" tool you can exercise great control over the process and selectively sharpen parts of an image, which is especially useful in the event of small focussing errors.

The "Sharpen" tool (which resides with the icons down the extreme left of the screen) is more correctly a brush and can sharpen small areas of detail if required. On occasions it can be worhwhile but is hard to use well and requires much practice to do so. Close examination often reveals lots of sharpening artifacts where it is used

The last sharpening facility I shall deal with is the "Adjust Sharpness" tool which sits immediately below the Unsharp Mask on the Enhance drop down menu. This tool is based on the excellent "Smart Sharpen" tool in CS3 and CS4. It was seriously intended to supplant the Unsharp Mask by approaching the compromise between sharpness and noise from a different direction. It retains the Amount and Radius settings for sharpness control but omits the important Threshold slider which serves to minimise increasing noise while sharpening.

Most noise is evident in shadow areas and so in the Smart Sharpen tool a flexible facility is provided for fading the effects of sharpening in noise prone areas. Very clever. It also incorporates a means of minimising motion blur with an "angle" dial. Theoretically it can tidy up some pictures made blurry or soft by slight camera movement in a way previously denied us.

All of this is very flexible, very powerful and calculated to improve an image's perceived sharpness with a minimum of damage to fine detail.

Unfortunately, when transferring Smart Sharpen to Elements in the form of the Adjust Sharpness tool, the designers (for some reason which leaves me astounded) removed the powerful "Shadows" and "Highlights" tabs which facilitate sharpening without highlighting noise. Consequently, for most images, most of the time, Adjust Sharpness in Elements is effectively the Unsharp Mask with the Threshold setting taken away. What (may I humbly ask) was the point of that? Words fail me. Of course the motion blur removal device is still present but I have yet to be entirely convinced of its benefit in practice.

Well that's all for now. Next time I shall look at Noise Reduction in Elements ... oh and Merry Christmas!

Sunday, December 21, 2008

Sharpening in Elements part 3

The big problem with the Unsharp Mask is that while you DO get visual feedback about your sharpening parameter settings at the time of using it, you eventually have to commit yourself by hitting the OK button. Later, having stared at the image some more, you might easily conclude that you've overdone it, not gone far enough or got the balance of parameter values wrong for your display application. If you've saved the sharpened image you then have to revert to your sooc version (hopefully you DID rename the edited file) to begin the various edit steps again. If you haven't saved the sharpened image then you must go to the Undo History window, revert to the step before Unsharp Mask and re-do it. Then eventually you may change your mind again. Surely there's a better way - a way to fine tune your work as you go.

Here is a workflow approach to sharpening jpeg image files (and we ARE talking about jpegs) which largely solves the fine-tune problems and save a lot of time (and hassle) in the long run.

Ahem! The Hobbs Method:

Open your sooc image, determine that it is worth editing.

  1. Save it as a new filename, perform exposure, colour, cropping and any repair edits
  2. Go to the "Layer" menu at the top of the screen and click on "Duplicate Layer"
  3. Perform a strong general sharpen (say) Amount 300; Radius 1.8; Threshold 3 OK
  4. Go to the Palette Bin Layer window and click the little down arrowhead next to "Opacity". A slider appears which monitors and fine tunes your sharpen from 100% back to zero
  5. When you are satisfied with the result, save it as a default .psd file
  6. Go back to the Layer menu and click "Flatten Image"
  7. Save the file as a jpeg.
There! That wasn't so hard was it? But what did we accomplish with all of that?

For a start we preserved the original sooc file - just in case. Secondly we saved an edited .psd file. Thirdly, we saved a completely finished, ready-to-use jpeg. Let us suppose that, later on, we decide that we got the sharpening wrong for our purpose in the jpeg and that we need to fix it. We COULD go to the sooc file but that means we have to redo all of the other edits, which (depending on the file) could take ages. Instead we go to the .psd file. Here we find that the duplicate layer is still in place, which allows us - using the opacity slider to quickly change the fine tune before saving a new jpeg. At worst we delete the original duplicate layer, do an entirely new sharpen run and fine tune again.

This is the best way I know to time efficiently edit a jpeg file while being able to quickly amend sharpening as needed for any purpose. At the same time we have been able to fine tune our sharpening in a way not normally offered by the Unsharp Mask.

There may be some who are not certain what actually happened in the Layers jiggery pokery. When we created the Duplicate Layer, our subsequent sharpen was performed on that layer alone, leaving the original "Background" layer completely untouched. When the Opacity is set to 100%, all we can see is the sharpened image on top. As we progressively move the slider back toward zero, more and more of the sharpened overlay is progressively made transparent, until at 0%, it is completely erased, revealing the original unsharpened image. We just move the slider back and forth between "completely sharpened" and "not sharpened at all" until we feel the compromise is finally right. Coool!

Next time we'll look at the "Adjust Sharpness" command.

See my work at: www.pbase.com/davidhobbs

Saturday, December 20, 2008

Sharpening in Elements part 2

Let's return to our Unsharp Mask dialogue box and to the matter of the parameter values. There are several considerations which, for me, influence the Unsharp Mask parameter values. They are:

  1. The overall condition of the image
  2. The amount of noise in the image
  3. The subject style of the image
  4. The final intended image display format

IMAGE CONDITION

If we are confronted by a genuinely POOR image, unless the content is important and unable to be re-shot, I am inclined to reject it altogether. Experience has taught me that, beyond a certain point, it will always be a matter of rubbish in - rubbish out.

On the other hand it seems clear that if a sooc (straight out of camera) image happens to be well nigh perfect (a somewhat rare event) SOME sharpening will always be a good idea, but not very much. When I say well nigh perfect I mean:

  • No discernable camera movement or out of focus softness
  • No readily discernable noise
  • No significant adjustment of exposure required
  • No white balance adjustment required
There is ample evidence that Amount values over 100 and Radius values over 1.0 can allow some sharpening halos to become visible under close examination. Sharpening halos (i.e. previously described highlight lines along edges) are always present, but in some parts of an image they will be more noticeable than others, particularly as halo lines become brighter and/or wider.

For a full sized near-perfect sooc image which will only ever be viewed on a computer screen and likely to be scrutinised by a pixel peeper, the best Unsharp Mask values could easily be as follows

Amount: 100
Radius: 0.5
Threshold: 0

IMAGE NOISE

If an image has been shot at high ISO values, it will probably show noise, especially in shadow areas. If the image is underexposed and has to be brightened, the noise will be enhanced in the process. If colour saturation and/or white balance has to be adjusted, chrominance (i.e. colour) noise will be further elevated. In sharpening the image, we have to avoid making the problem still worse.

If the noise is only really visible under pixel peeping and the final form of the image will be (say) a 6x4 inch print, noise reduction may do more harm than good. During sharpening we should set the Threshold value to about 5. When the Threshold is 0, virtually everything in an image will be regarded as large enough to have an "edge" around it and thus be deserving of a sharpening halo. Because of this, masses of tiny noise artifacts will effectively be enlarged and made more noticeable. As we increase the Threshold value, progressively larger objects (most especially the noise) are omitted from the sharpening process. Thus important features of the image receive sharpening while existing noise artifacts should be made no worse.

Unfortunately the subjective effect of increasing Threshold values is to reduce the overall impact of the sharpening process. Accordingly it becomes necessary to bump up the Amount and Radius values to retain the visual impact of having sharpened an image while avoiding noise enhancement. So for a somewhat noisy but otherwise acceptable image, Unsharp Mask parameters might well be:

Amount: 180
Radius: 0.9
Threshold: 5

IMAGE SUBJECT STYLE

Once again, let us assume that our sooc image is basically excellent but we still want to overcome its anti-aliasing filtering and incomplete camera sharpening. The parameter values may be influenced by the subject style of the image itself.

Let us first imagine a truly complex mega-edge image such as a garden with masses of shrubs and trees with many many thousands of leaves, petals, twigs, compost bits, pebbles, blades of grass etc etc. A lot of these features start to assume the size of the noise particles in our last example. If we set our Threshold value too low, the image is made more muzzy by the thousands of tiny halos. It becomes actually harder to identify objects in the image than it may have been before. Unless there are some features of the image that are less edge dense, there may be a sound argument for not sharpening at all. However it is usually true that some features of such an image - such as people or statues etc (which are indeed less edge dense) may indeed benefit from sharpening.

It may be best to retain a high Threshold value so as to leave the millions of leaves and gravel pieces in relative peace while still sharpening the people. A low Radius value might also be a good notion, while to compensate, one might consider a slightly higher Amount value.

Amount: 200
Radius: 0.5
Threshold: 5

Some image styles are inherently short of prominent edges and the edges which DO appear, might well be low contrast in nature. Such images might include close ups of faces with large expanses of fairly feautureless skin or close ups of flower heads in which the main features are delicate fibrous patterns in petals and large leaves.

In such cases we may WANT to highlight fine texture and may WANT to emphasise subtle edges. You may like to try parameter values such as:

Amount: 200
Radius: 1.5
Threshold: 1

INTENDED IMAGE DISPLAY FORMAT

Once upon a time, the vast majority of images captured by cameras were either intended for privately viewed prints or commercially published transparencies ... and that was basically that.

These days the situation has changed. Vast numbers of images may never reach paper. Most pictures taken for private/family consumption will never be published, never even be printed for display in frames and albums. Indeed most will never be anything other than digital images for display on computers, electronic display frames and/or television sets. Even then, many will stay full size while vast numbers will be resized down for use in emails or on web galleries.

Small prints, large prints, published prints, slideshow images, resized images. All of these intended uses embody different considerations when post processing. The issue often requiring the most thought will be sharpening. Indeed many photographers will not sharpen their processed images AT ALL until final intended display formats and applications have been determined. They will then sharpen particular versions for particular applications

Leaving aside the considerations already discussed, these are some VERY GENERAL suggested parameters for particular display applications:

Prints in general will benefit from extra sharpening as the process of printing will tend to rob many images of their sharpness, while noise seems generally less prominent in prints than it might be on a computer screen:

Amount: 200
Radius: 0.7
Threshold: 0

Images resized down for email or web gallery display will benefit from increased radius. Halos which might have been visible full size, may not be when everything has been proportionally reduced. Assuming you sharpen an image BEFORE scaling it down, the parameter values might be:

Amount: 200
Radius: 1.5
Threshhold: 3

And so on and so on. In the end, each of us has to make a decision based on many considerations. There will never be ONE correct set of values in every case. Experiment for yourself based on the suggested values. In the next article we'll examine an approach for more accurately customising our sharpening for individual images.

See my work at: www.pbase.com/davidhobbs

Friday, December 19, 2008

Sharpening in Elements

The vast majority of images which I edit, undergo four processes:

  1. Adjust Exposure/Contrast
  2. Adjust Colour Intensity/Temperature
  3. Adjust Composition (cropping)
  4. Adjust Sharpness

We have already dealt with the first two. Elements' excellent cropping tool is almost self explanatory but there are a few little points I'd like to discuss concerning it, another time. This article is about sharpening.

Virtually all camera sensors to date incorporate an anti-aliasing filter which is intended to lessen the potential effects of pixellation in digital images. One could understand its use in days of yore when resolution was always low but in this era of Nikon D3xs and Canon 5D mkIIs with 20 odd megapixels of resolution, one wonders why it is necessary to worry about anti-aliasing. Still, I suppose engineers (as opposed to marketing gurus) know best.

The point is that anti-aliasing filters deliberately blur images. If there was no sharpening of digital images at all, they wouldn't look very impressive. As it is, (unless you are shooting RAW files - and not always then) nearly all cameras perform SOME sharpening to images before you even see them. Let's be clear. Most "straight out of the camera" images have ALREADY been sharpened.

High pixel density point & shoot type cameras tend to sharpen images more than relatively low pixel density DSLRs. This is because it is assumed by the designers that p&s shooters won't want to be bothered with post processing at all and that the in-camera sharpening is the only sharpening that will ever happen. If you own a point & shoot/compact style camera I would strongly recommend that you go into your camera's menus and turn the in-camera sharpening effect down. Each make & model of camera will be different in this regard and it pays to experiment. The point is that if the original image is already a little oversharp, further sharpening in post processing will mostly serve to highlight whatever noise may exist in the image, create processing artifacts and produce prominent sharpening halos. Yuck!

Most often, while the sooc (straight out of camera) image may have received a slight degree of sharpening in-camera, it will still be a relatively soft picture, still requiring post process sharpening to look its best. Fortunately it is in the nature of post processing that adjustments like sharpening can be properly controlled and monitored - at least in theory.

We return to our cow from the end of the last article which you should open in Elements. Go to the Enhance drop down menu. In the first section of options there is an "Auto Sharpen" tool which often works quite well. I want you to ignore it however because of the fact that it affords you no manual control and no opportunity to learn about the process. It fails to take into account how an image will ultimately be used. It effectively behaves like the original, dumb, in-camera facility. Let's leave it.

In the third section of options there are two sharpening tools. They are "Unsharp Mask" and "Adjust Sharpness". As it happens, both are excellent.

Unsharp Mask is the venerable Photoshop tool with the odd name. Explanations regarding how this tool was developed and how it got its name may be found in various places on the web so I won't go into that here. Let's just look at the classic dialogue box and examine the three parameters:

  1. Amount
  2. Radius
  3. Threshold
Sharpening is performed by effectively increasing the contrast along edges. Edges are defined by one tone/colour being aligned with a DIFFERENT tone/colour. When an edge is selected for sharpening, the lighter tone/colour side of the edge is further lightened immediately next to the edge and fades gradually back to the original tone/colour as one moves away from the edge. Likewise the darker tone/colour side is further darkened along the actual edge and fades back as you move away.

Simplistically explained, the Amount describes the DEGREE of lightening or darkening which takes place during a sharpening operation. The Radius describes the WIDTH of the area on either side of the edge which is affected by lightening/darkening. The Threshold describes the SIZE of an image area which the software will recognise as an edge in the first place.

Just for the hell of it. Let us enter the following values for the Unsharp Mask dialogue box by moving the respective sliders:

Amount: 300
Radius: 1.2
Threshold 3















Click on OK and there is our cow all sharpened. In the next article we shall examine parameter values in some detail.

See my work at: www.pbase.com/davidhobbs

Thursday, December 18, 2008

Adjusting Colour in Elements














For the purposes of the exercise I am going to cheat a little here. We have returned to our picture of the cow but I have reduced the colour saturation and raised its colour temperature a fraction in order to demonstrate two of the nice colour adjustment tools in Elements.


Click on Enhance and then "Adjust Color" (Americans will never learn to spell - sigh!). We see eight options on a new drop down menu. "Remove Color Cast" is a little superfluous if we used the eyedroppers in Adjust Lighting during the last exercise. In any event it behaves very much as an "auto" command, taking fine control out of one's hand. "Remove Color" is a crude black & white conversion tool which doesn't work nearly as well as the earlier "Convert to Black and White" tool.

"Replace Color" is a potentially powerful tool to manipulate particular colours within the image while leaving others alone. It can be fun to use but I have never been motivated to use it during real life post processing. "Adjust Color for Skin Tone" is also a potentially powerful tool which in practice I never use much, given that when other aspects of an image's exposure and colour balance have been dealt with, the need for it mostly goes away. "Defringing Layer" might be useful but I have never seen an application for it, thus far.

"Color Variations" is a fun way to adjust colour temperature, remove color casts and generally tinker. It offers lots of genuine fine tuning but at the end of the day is a much slower way to go about things than its alternatives. "Adjust Color Curves" looks at first glance as if it might be powerful but compared to the "Curves" tool in Photoshop and indeed Elements' own Levels control it's a bit of a toy really. There's more to be said about Adjust Color Curves ... but take my advice and don't bother with it.


That leaves "Hue/Saturation" which potentially gives you almost complete control over everything to do with colour with the aid of calibrated sliders. In practice I'd recommend you concentrate mostly on "Saturation", for the most part limiting its manipulation between +/- 20. This facility also offers interesting coloration options for black and white images such as various types of sepia etc

Okay, lets bump up Saturation to +20 on our cow.

For some obscure reason the Elements' designers decided to hide a very useful tool in a very strange place. If you look at the top of the Palette Bin you see three edit tabs: "Full", "Quick" and "Guided". The vast majority of what we will do will be in the Full area but if you click on Quick and move your eye directly down the screen you come to the "Color" section with its immensely handy "Temperature" slider. All of the Quick controls are potentially useful but they lack proper calibration. There is no numerical value attached to your adjustments, disallowing reference points for use in more difficult images. Nonetheless I think the Temperature control is the BEST such tool in either Elements OR Photoshop for that matter. It almost makes RAW files redundant in their ability to "re-shoot" an image with a different white balance.

Sometimes a simple tool is the best and Temperature is a case in point. Slide right to lower the temperature of the image. Slide left to raise the temperature. Sometimes in order to go for particular effects, such as simulating sunset lighting, this tool is invaluable. Often the white balance control in cameras is inaccurate. This little tool can fix the problem. Brilliant. Take my advice however and underadjust rather than overadjust.

I can't give you a reference value (damn it!) but for our cow, lets lower the colour temperature just a smidge ... maybe a full tad. Mmmmmmmm ... I may have gone a bit too far, but you get the idea

In summary, the most useful colour adjustment tools are Enhance - Adjust Hue/Saturation PLUS Quick- Color -Temperature.














See my work at www.pbase.com/davidhobbs

Monday, December 15, 2008

Adjusting Exposure in Elements















Here's a picture of a Hereford cow, shot with my Sigma 120-400 attached to one of my D80s. The image is not perfect or especially interesting but it's not bad for an exercise. Exposure is a fraction dark but there's no discernable camera movement or focus problems. I like the basic composition. But the whole thing could look a lot better than it already does. Let's post process it.

Let's start with contrast and exposure

Okay, we open it in Elements and click on "Enhance". We are confronted with a drop down menu containing a series of options in three sections. The first section shows a sequence of 6 "auto" commands. I don't just reject these facilities out of hand. I have experiemented with them to see how well they work. I have to admit that some of them actually work quite well .... SOMETIMES. Unfortunately one is never quite sure when they are going to give good results or not. A good third to half of the time they overdo things or else get things plain wrong. You then have to go back to square one and start again. You have wasted time and the black box nature of "auto" commands has ensured that the user has advanced his/her image processing skills not at all.

I won't bore you with experiments right now, but when you start using Elements yourself please DO experiment and form your own opinion. For now, let's just let my experiences (okay, maybe my prejudices as well) hold sway.

In the next section of Enhance options, assuming we are not going to use the surprisingly excellent "Convert to Black and White" and assuming that we have no interest fooling with the not especially smart "Smart Fix" command, we are left with "Adjust Lighting" and "Adjust Colour". Whoopeee! Down to business at last.

In Elements parlance, what we are needing to do is adjust lighting and so we click on that option. We are greeted with three sub options: "Shadows/Highlights", "Brightness/Contrast" and "Levels". Shadows/Highlights has a specific use to solve particular problems and I'll discuss it another time. Brightness/Contrast is a simple command for adjusting an image's exposure but it has major limitations. I urge you to make the powerful Levels facility your exposure adjustment implement of choice.

When you click on Levels a new window comes up as illustrated below.

The options are many but everything that you do is instantly monitored by the histogram in the centre as a double check against the actual appearance of the image. The default histogram is a compilation of all three colour channels i.e. red, green and blue although you can examine each channel separately if you wish. Let's leave the composite histogram as it is.

You see three sliders under the histogram. The white one adjusts highlights, the black one unsurprisingly adjusts shadows while the grey one adjusts the mid-tones. As a general rule to begin with, the highlight slider should be moved progressively to the left, such that it reaches the uppermost extreme of the histogram without clipping (i.e. blowing) highlights. The shadow slider should then be moved progressively to the right until it reaches the histogram without losing shadow detail. Hopefully the mid-tone slider can be left in peace.

Of course the Levels facility is cleverer than that. As you move the highlights and shadows sliders you can view the appearance of clipping in great detail by pressing the "Alt" key at the same time. The picture turns totally black and as clipping in each of the channels commences, sections of the image are revealed in red, green or blue. When all three channels clip together, the sections turn white. You can clearly see clipping occur from its very origins. Releasing the Alt key at any time allows you to see the extent to which actual channel clipping effects the appearance of the image. Brilliant!

Another way to adjust the contrast and exposure is to use the "eyedroppers". Click on the highlight eyedropper and click on any part of the image which SHOULD be completely white. In this case, click on the area immediately to the right of the cow's nostrils. Voila. All the other tones fall into place, simultaneously doing a great deal to sort white balance. Take the shadow eyedropper and click on something which should be black such as the cow's eye. Once again darker portions of the image should adjust themselves. How easy! If you feel that the whites are too white or the blacks too dark, go to the "Output Levels" sliders and fine tune the results by a few points. If shadow areas do not reveal enough detail, nudge the mid-tones slider a little to the left. If the image seems a little harsh or overbright, nudge the mid-tones slider a fraction to the right.

The final overall result should be as close to a perfect exposure and contrast result as can be made - and you've been in total manual control the whole while.

In summary then - if you want to fine tune an image's exposure and contrast, go immediately to Enhance - Levels. As far I can see, it is the only way to fly.

See my work at: www.pbase.com/davidhobbs

Tuesday, December 9, 2008

Setting up Elements

I can't possibly hope to teach the complete use of Elements in a series of blog articles. Rather, I want to discuss an "approach" to its use - to demonstrate the extent to which a careful selection of Elements features (at an expenditure of $AUD199) can go a long way toward impersonating the venerable Photoshop (at an expenditure of $AUD1099).

Let's confine ourselves to the "EDIT" strand of Elements. While the "CREATE" and "SHARE" strands are very functional I have my own approaches to such things in which programs like Elements don't often play a part. That's just me and I am far too old and ugly to change now.

Anyway, the Elements version 6 interface screen can be customised to some extent and I would strongly recommend you doing so. I like a simple set up with as much image display space as possible. For this reason, I put away the "Project Bin" at the bottom of the screen but I like to keep the "Palette Bin" on the right. In the "Full" Palette Bin I keep only two windows open on a default basis. They are "Layers" and "Undo History". I find that I use those more than anything else. In Photoshop I also like the "Actions" window but (regretably) the lack of Actions capability is possibly Elements' biggest single shortcoming.

Ensure that at the top of the Palette Bin you have selected the "Full" (as opposed to "Quick" or "Guided") options. If you click on "Window" at the top of the screen a choice of additional facilities will be made available to you. "Navigator" has zoom and search abilities which LOOK as if they'll be useful. In reality I find them slower and less precise than alternative controls. "Histograms" are sometimes very useful but there are better ways to access these visual aids than through a permanent window taking up so much space. "Favourites" and "Content" are useful along with "Effects" and "Colour Swatches" if you are using Elements as a graphics design aid, but such is not our purpose here.

Some of the less useful windows are defaults when you first open Elements. To get rid of them, pull them out of the Palette Bin, click on the little white "more" menu, uncheck the "Place in Palette Bin when Closed" option at the top and click on the close window "X" in the extreme top right of the window. Go up to the Window menu at the top of the screen, choose Undo History and Layers, place them in the Palette Bin, and check the "Place in Palette Bin when Closed" option for each. Also ensure that the useful and tidy "Tools" palette is checked and resident down the extreme left of screen.

There - we have set up our Elements Edit screen and are ready to explore its tools.

See my work at: www.pbase.com/davidhobbs

Sunday, December 7, 2008

Getting into Elements















There is now an amazing number of software packages devoted to post processing of images. Some of these are genuinely excellent. A good many are pitched at people seeking "dumb down appeal" at the expense of actual performance. Such programs are festooned with features commencing with "auto-" or "smart-". I always get a little wary when confronted by commands which serve to take fine adjustment out of my hands.

This "computer knows best" approach is often the very reason that post processing of a given image was made necessary in the first place. Crude adjustments made by "auto" or "smart" fixated cameras at the instant of capture have very often gotten our pictures into trouble in the first place. Surely more of the same may just make the problems worse. If one is going to post process images, let's give control back to the photographer. Accordingly a lot of "easy", "quick", "auto" and "smart" style software packages are actually less than suitable for our purpose.

At its CS4 evolutionary state, Adobe Photoshop represents the last word in power, flexibility and precision when optimising images. It allows users to retain meticulous control of what they are doing while at the same time affording them powerful means for creating and fine tuning macro commands to take away the drudgery. It facilitates the "plugging in" of external programs to replace or augment inbuilt functions. Dozens of monthly magazines devoted to Photoshop adorn newsagency racks while many thousands of websites offer articles, courses, plug-ins, tutorials and advice on the subject.

If you have decided to post process images, using Photoshop attaches you to a world wide community of photographers all trying to do the same thing with the same tools. While any individual like you or I will never hope to master every intricate Photoshop skill by ourselves, the world-wide Photoshop user base collectively knows every last nook and cranny of its astounding capabilities. Choosing Photoshop over a less prominent package is a very good way to start your digital darkroom education.

The pity is that the full version of Photoshop is very expensive. Even upgrading to the latest version from earlier ones isn't especially cheap - particularly when you are doing it every 18 months or so.

For this reason I frequently recommend Adobe Photoshop Elements. Years ago they used to call the cut down version of Photoshop, "Photoshop LE" (Light Edition). The interface looked exactly like the full version and it wasn't always easy to work out what was really missing from the senior package. These days the situation has changed, "Elements" is still a cut down "Photoshop" but the interface is now quite different and a whole host of populist features have been tacked on - lots of "auto" this and "smart" that along with cosy "sharing", "creating" and file management facilities.

If you know where to look however, you can still dig up and utilise a kurnell of late-model Photoshop routines and facilities which allows Elements to substitute for the real thing quite nicely. In the blogs to come I am going to share with you how I have learned to strip Elements of its tinsell window dressing and utilise it as a serious substitute for the mother program. At the end of the day, if you get your skills moving on the "Photoshop" part of "Photoshop Elements" you will have a great headstart toward learning the full program later.

Check out my work at: www.pbase.com/davidhobbs

Thursday, December 4, 2008

Still looking for the truth






















Does an important subject deserve one's best efforts in seeking a good image or will bravado, convenience and incompetence suffice? After all, an image like this one only has to last fifty years or so.

A lot of macho shooters, grew up taking film to the local camera shop or chemist. They'd get back their prints and were usually delighted with what they received. Images seemed consistently well exposed with good contrast. One can jump to any one (or a combination) of three possible conclusions.

  1. Modern exposure meters are basically infallible and will virtually always produce terrific results. Post processing is unnecessary.
  2. The shooter (probably of the macho variety) must obviously be an expert photographer and all of those wishing to improve their efforts would do well to listen to whatever advice he may choose to offer. He says post processing is unnecessary.
  3. The person(s) deciding that their results are so brilliant, wouldn't know a good image if they stumbled over it in the half light and performed severe injury to a shin.

To all of this, allow me to make the following responses:

  1. After all these years and as sophisticated as the hardware/firmware camera implementations now are, exposure meter systems are FAR from infallible. They are constantly tricked by prevailing conditions into providing less than optimum results. Overexpose by a tiny fraction and you may easily blow highlights. Underexpose by a little and all those masses of shadow lose their detail. People who believe that "straight out of camera results" rarely need processing have never been in a commercial lab watching operators make constant brightness/contrast adjustments to images moving through to be printed
  2. No one is expert enough to get perfect "straight out of the camera" results every time. It just doesn't happen - even images that look fine on the rear LCD preview screens can turn out to be unsatisfactory when examined under ideal conditions. Few casual shooters will take the time, during shoots, to meticulously examine preview screens for cropped histograms, poor focus, inaccurate colour balance and camera movement problems. In most cases, if the subject is important and you wish to honour it with a genuinely good image, post processing is essential

  3. It has taken me most of my lifetime to be able to assess the technical and artisitic merit of photographic images and I don't always get it right NOW. I DO know that there are few images displayed for me by well meaning macho shooters that could be described as something I'd have been proud of. Most casual photographers delude themselves into ignoring most of the constituent elements of what constitutes a good (as opposed to a serviceable) picture.

Let's examine a theoretical but all too common style of image (NOT the one above).

Yes it IS a lovely picture of the new baby. You can see who it is, she is smiling, the bright yellow shawl does indeed look bright yellow and the top of the subject's head has indeed NOT been chopped off. For most people (even toffee nosed types like me) the content of the image may make it a wonderful keepsake for the whole of their lives. No argument. But don't start telling me it necessarily does its beloved subject justice or that post processing might not have assisted it to BECOME a genuinely good image.

Why couldn't the image have been cropped so that the 40% of the image display area, presently occupied by the cot, be removed? Why couldn't the image be sharpened a little to help compensate for the inaccurate focus and/or slight camera movement blur? Why couldn't the exposure be adjusted so that the left side of the child's face is no longer lost in almost featureless shadow? Why couldn't the white balance be adjusted so that child's face, (lit by tungsten light) be less orange? Why couldn't the transient spec of anonymous vomit (presently adorning the baby's chin) be removed?

If a subject has value, surely it is a dishonour to that subject if every effort is not made to reproduce its image as competently as possible. To anyone with this level of sensitivity, it requires thoughtful camera work, some actual knowledge of imaging ... oh yes .... and post processing.

My work can be seen at: www.pbase.com/davidhobbs

Monday, December 1, 2008

The truth is out there ... somewhere















Agent Scully - could this be the truth at last? Go on - play the theme music. Duddlee Da Da Da .... Dee Da Doo Da ....

Among the macho amateur photographer fraternity is an endearing belief that what comes directly out of the camera is really the truth. What happens after that, presumably carried out by fast talking people with slicked back hair, white shoes, sunglasses, loud jewellery and pink suits (with the aid of computers and Photoshop) is some kind of DISTORTION of the truth. "Let's expose these deceitful Photoshop confidence tricksters who represent their doubtful alchemy as the REAL truth. Harrumph!"

In the words of the immortal Thadeus D. Hoppenheimer ... "Give me a break".

If we are going to expose something, let's expose, once and for all, this notion that what comes directly out of a digital camera is really the pure unsullied truth and that post processing is the instrument of its pollution.

Let's leave aside (for the present) the question of correct shutter speed and aperture. Let us assume that our macho shooter (hereafter known as MS) somehow manages to get the image exposure settings spot on every time in his search for the truth. Such a feat would be truly incredible ... BUT ... let's assume it anyway. We'll come back to the metering issue another time.

We'd better define what "the truth" means before moving on. In the absence of something more philosophically rigorous, let's say that MS's truth is "what he originally saw before deciding to take a picture". Okay, let's go with that.

MS takes a picture with his digital camera. It is the best exposure that can be expected. He examines it in his computer, prints it out on his dot matrix printer or else takes it to the lab at K-mart to get a print made. MS doesn't believe in "cheating" with Photoshop and so we know that he didn't shoot it as a RAW file (which requires post processing). Nor did he intentionally manipulate it in any way with computer software.

Is the image in the print, that he holds in his hand, the truth? Almost certainly not.

His girlfriend, the central subject of the picture was originally some distance away but was brought closer than MS's original natural view by his zoom lens. The image is not what he actually saw with his eyes. By MS's strict standards it must already be an untruth. MS's nice landscape was framed to omit the overflowing rubbish bin just to the left. Untruth. The landscape features a setting sun and the image shows bits of lens flare. Untruth. The trees to the right are actually much darker than MS saw because the bright sun caused the camera's exposure metre to render them in silhouette. Untruth. Good photographer that MS is, he brightened his girl friend's face with fill in flash so that it wouldn't be rendered as a dark outline by the sunset. The result could not possibly have been seen before the decision to shoot was made. By definition it is an untruth.

Once he takes the purist route, MS is immediately in trouble. As soon as a decision to take a picture is made, MS's "untruths" are inevitable. Some arise from the fact that large amounts of the scene he originally saw are inevitably cropped out - either on purpose or because not everything in his field of vision can possibly remain in shot. Some arise because of the inherent limitations of cameras and lenses. When shooting directly into the sun, lens flare is virtually inevitable. Likewise, the dynamic range of a digital sensor is severely limited. Detail will inevitably be lost at either the shadow or highlight end (or both), such that the trees which originally showed green detail are now black outlines. If he was using a fast lens and/or was especially clever, background may be pleasingly reproduced out of focus, bringing the girlfriend's face into sharp relief. It may make a great picture but it "wasn't what MS originally saw". UNTRUTH.

But MS can go forward content in the knowledge that he didn't ... heaven forbid ... "photoshop" it. Of course if MS HAD photoshopped it, he might have been able to remove that untruthful lens flare, restore those untruthful tree silhouettes and retrieve truthful detail in his girlfriend's hair highlights. But let's not worry MS with inconvenient details like that.

The irony of it all is that MS's allegedly unsullied picture has ALREADY been well and truly "photoshopped" in a manner of speaking. Because he didn't shoot RAW, his camera's JPEG firmware has taken it upon itself to process the image in a number of ways.

  • The camera has almost certainly artificially sharpened the image. All digital sensors have anti-aliasing filters which blur images slightly to reduce the appearance of pixellation. In producing displayable imagefile formats, pictures are routinely sharpened to some extent.
  • The camera has probably enhanced the image colour. Industry research reveals that most people "remember" more colour in a scene than is strictly captured by a digital camera. To deliver a popular colour effect, images are usually auto-processed in-camera to saturate them a little.
  • Sometimes at high ISO settings, camera firmware automatically DEsaturates colour in order to minimise noise.
  • Depending upon the settings, the firmware will deliver a relatively wide range of contrast values.
  • However good the auto-exposure may be, white balance, as determined by camera firmware, is often wildly inaccurate.

The proposition that an image direct from a digital camera is always the inviolate truth is highly questionable at best. Digital cameras and the very notion of image capture are imperfect in themselves. Usually the image "straight out of the camera", has already been processed - often inaccurately. It may be time for MS and all of his ilk to cast aside their comfy delusions.

Whatever the camera does to images can only be controlled imperfectly in the heat of the moment at the actual time of exposure. Camera settings and their effects are crude at best. The whole point of post processing is that image parameters can be adjusted at one's leisure using genuinely fine gradations to arrive at the best approximation of the truth possible.

Is there more to say on this subject? You bet! I am only getting warmed up.

See my work at: www.pbase.com/davidhobbs