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-   -   Tutorial Pete's Photoshop tricks (https://e-group.uk.net/forum/showthread.php?t=10943)

snaarman 14th September 2010 08:03 PM

Pete's Photoshop tricks
 
I thought I might show some Photoshop and Camera tricks I use from time to time. It may be you know these already: However - some of them I only discovered recently, so one is never to old to learn eh? These apply to CS3 and probably the newer versions as well. Some of the tricks don't work in Elements I'm afraid. I thought Elements was the bees knees until I blew a load of dosh on CS3 and discovered it is both better and faster than Elements...

Anyway - to start with, here is a recent trick, pointed out in a camera magazine this month. Using the Shadow/Highlight adjustment feature in Photoshop. (Don't try this in Elements, as the version there is a bit too crude and from experience gives poor results. The CS3 version sports 8 sliders to Elements 3, so you can be a lot more subtle).

First start with your raw file via ACR. Hopefully you got things reasonably correct in the camera :) but now is the time to adjust the Exposure slider slightly to get the histogram just up to the left and right limits without hitting the ends too hard...

Here is one I took earlier. Oh dear - there is just too much dynamic range in the image really. I generally use centre weight metering - so the rocks and the sky were fighting to influence the exposure and the result is a compromise...

http://e-group.uk.net/gallery/data/6...nversion_1.jpg

By the way, I always export from ACR in 16 bit mode to retain maximum information during editing. CS3 is happy with 16 bit images, but I recall some parts of Elements prefer 8 bit mode.

I used the Shadows/Highlights adjutment to pull back the sky and lift the rocks slightly. You can adjust the radius for the effects to minimise the dreaded halo effect, and here are a couple of results with a before and after crop..

http://e-group.uk.net/gallery/data/622/62188981A.jpg

http://e-group.uk.net/gallery/data/622/62188978A.jpg

Notice how we have pulled back the sky, lifted the shadows, avoided over-obvious halos and generally kept the processing subtle..

Clearly these shots were not suitable for the classic bracketed HDR approach as there's a lot of movement involved - plus: working that close to the sea with a tripod?? I don't think so.

Thinking of HDR and tonemapping, here is another CS3 dynamic range trick I read about. How to force Photoshop to do basic tonemapping when you didn't start with a HDR image:

I started with the usual 16 bit image I get from ACR and I converted it to 32 bit mode, then I changed the mode straight back to 8 bits. Now you get a chance to use Local Adaptation to rescue those highlights and shadows in a different way.

http://e-group.uk.net/gallery/data/622/fake_tonemap.jpg

You click on the little button to get more options and there is the curve tool box. Note that I have tamed the otherwise mad curve tool by specifying each dot as a corner - so I get a 5 line correction curve. You can save this curve for your next CS3 session. Obviously the curve won't be right for a different image but its quite a good place to start. I find its easier to work on the tonemapping curve in individual sections by dragging the appropriate corner point.

Coming soon: Sharpening and rescuing really blown skies :o

Pete

theMusicMan 14th September 2010 08:14 PM

Re: Pete's Photoshop tricks
 
Smashing post, Pete. Thanks for this.

Zuiko 14th September 2010 08:24 PM

Re: Pete's Photoshop tricks
 
Excellent post and very informative. I'm looking forward to part two! :)

Nick Temple-Fry 14th September 2010 08:35 PM

Re: Pete's Photoshop tricks
 
Looks like you are starting an interesting series, though with a trick I can't convert to The GIMP.

But the trick I really want to hear about is affording Photoshop, can't wait for that one.:)

Nick

snaarman 14th September 2010 08:35 PM

Re: Pete's Photoshop tricks
 
Bonus! Second Photoshop trick in one day:

We've all done this: Blown a sky and taken the edge off an otherwise nice picture. You can try to rescue it using the highlight recovery slider in ACR, but beware, it leaves nastly double lines around your trees and mountains.

You could use tonemapping or Shadow/Highlight as in my first post, but they have their drawbacks, with the danger of halos being visible.

Here's a naughty little trick I sometimes use: This uses the graduated fill tool, and it works best on trees against a blown sky. Here is an example because a picture is worth a thousand word, or 2kbytes if you prefer..

http://e-group.uk.net/gallery/data/622/62239456A.jpg

Here is the procedure, and this does work in Elements: Click on the forground colour box, and use the eyedropper to pick up the bluest bit of the blown sky you can find. This pale blue will appear on the "select a colour" pop up window. Now using the colour range you see in the window to pick out a deeper blue about half way towards black. This is the blue the sky should have been (if you follow me). Select this so it becomes the new foreground colour.

Now use the graduated fill tool and set it for Foreground to Transparent. Set the density to somewhere between 15% and 20% and the mode to Darken (very important, that). Now drag your graduated fill from top down to a bit above the horizon and see how it turns out. You may need to try a couple of times with different density to get the best result. Ideally it turns the sky bluer, leaves a hint of cloud if there were any there, and it tries not to turn the tree blue.

Here's another example, in this case an old slide that had a badly blown sky... Its a simple but surprisingly effective trick.

http://e-group.uk.net/gallery/data/614/wreck97y.jpg

Simples *chr

Pete

PS. Use with care. If it was clearly a totally lousy day and there wasn't any blue up there, don't put blue in, 'cos it will look wrong. Instead select a dark grey and drag that as per the paragraph above. This will create a lowering sky that can be quite effective. All this is no subtitute for better weather ;-)

tomke 14th September 2010 09:13 PM

Re: Pete's Photoshop tricks
 
Thanks Pete for these tricks. I have just begun to work with Elements 8 and the tricks are undoubtedly useful! Plenty blown skies overhere, so I will give it a go. I await the next trick with interest.

snaarman 15th September 2010 08:45 AM

Re: Pete's Photoshop tricks
 
Some observations about ACR. (Apologies if you don't use raw file format)

Here's one of ACR's useful little secrets: Presets.

You can save the current slider settings (or subsets of them such as Lens Corrections) as your own preset. I have made Lens preset settings for my Zuiko zooms at the wide and tele ends. These presets correct any residual chromatic Abberation and any vignetting, not that is much to correct, but we want the best we can get,eh?

Start with the ACR tab for lens correction and adjust the CA correction for a bright object in the corner of the image. Note these settings. Next you need some translucent matt film to cover the lens, then point the camera at a very evenly lit white wall in order to create the flattest field you can. Now use the vignetting slider to get the corners the same brightness as the centre. I finally combine these two corrections and save as a named preset.

My other settings are for daylight colour correction. I chose an overcast day and images a known white target, then used the dropper tool in ACR to correct it to white. This gives you a custom colour temperature and a tint. I've save these as presets as well. (I guess one should repeat this for every lens but I think maybe that's a step too far)

The trick is that the lens preset doesn't affect the current colour balance, and the lighting preset doesn't undo the lens corrections...

Here's my list of presets:

http://e-group.uk.net/gallery/data/622/ACR1_presets.jpg

So I can correct for lighting and lens with just two clicks :)

Pete

snaarman 15th September 2010 09:46 AM

Re: Pete's Photoshop tricks
 
ACR observations part two: The forbidden sliders.

You get lots of adjustment sliders in ACR, and not all of them are good :-)
Generally I adjust Exposure and Blacks to optimise the histogram, that is to say reduce the amount of clipping at each end of the histogram. You do need to look at the image and consider what is in the frame. If there are no dark areas, then the histogram should not go right down to the black end.

However, here are two I use with caution: At first I thought the highlight Recovery slider was just great, it pulls back blown skies by magic. Then I found it was adding a thin double outline where the mountains and trees intersect the sky, so I stopped using it. Be aware that pulling exposure back also dials in the same recovery algorithm, even though the recovery slider doesn't seem to move. You can use Recovery carefully and get away with it, but don't go too far.


http://e-group.uk.net/gallery/data/622/ACR2_sliders.jpg

The next Bad Slider is the Fill Light control. Just great for lifting those shadows. Hmm, the lifted shadows often bring a lot of noise with them. Again, use sparingly.

In fact I make a point of "exposing to the right" or mildly overexposing if you prefer. I am so conviced by this that I have set my E620 for global exposure offset of +3/6th EV (its an entry down at the bottom of the cogs menus). In my opinion an overexposed picture than has been darkened looks better than an underexposed one that has been lifted, mainly from the point of view of noise.

Pete

tomke 15th September 2010 12:03 PM

Re: Pete's Photoshop tricks
 
Just a question: Is there a difference between ACR for Elements 8 and ACR for CS? You use 8 tabs, I've got 3. I use version 6.1 for E30 and E-PL1 and can't find anything about any differences on the net.

snaarman 15th September 2010 12:08 PM

Re: Pete's Photoshop tricks
 
Quote:

Originally Posted by tomke (Post 84446)
Just a question: Is there a difference between ACR for Elements 8 and ACR for CS? You use 8 tabs, I've got 3. I use version 6.1 for E30 and E-PL1 and can't find anything about any differences on the net.

I think you use the same ACR, but it ends up looking different.. I have Elements 5 and I've used ACR with it. You only get 3 tabs which is annoying because I bet the other tabs are available but disabled by a switch somewhere in Elements.:mad:

Pete

PS. A couple of years ago I wanted to use a XP Home laptop with a video projector. It doesn't let you do that in the way I wanted (different output on projector to laptop screen) what you need is XP Pro, sir. Hmm. Search internet, and locate a secret registry switch that allows you to run a projector exactly as I wanted.

Result!

stevednp3 15th September 2010 12:10 PM

Re: Pete's Photoshop tricks
 
Thanks very much Pete, very good of you to take the time to share this info *chr

tomke 15th September 2010 03:54 PM

Re: Pete's Photoshop tricks
 
Thanks for your reaction Pete. Will go on with my search on internet then. It might be something with Vista, I don't know. Perhaps I will be able to find a solution.

Bikie John 15th September 2010 04:25 PM

Re: Pete's Photoshop tricks
 
Just to add a little snippet to Pete's comments about using the Exposure and Blacks sliders to optimise the histogram:

If you press the Alt key (for Windoze, not sure what the Mac equivalent is) while adjusting the slider the image display changes to show highlight or shadow clipping as appropriate. This means you can see which areas are going to block or blow as you pull them in. Hard to describe but much easier to see. It also works for (highlight) Recovery but appears not to for Fill Light.

Ciao ... John

CaptainD 15th September 2010 04:29 PM

Re: Pete's Photoshop tricks
 
Dear Pete,

Thanks so much for posting this extremely interesting post, much appreciated. I will have to have a play with this technique.

Cheers

Chris *chr

snaarman 15th September 2010 05:39 PM

Re: Pete's Photoshop tricks
 
Quote:

Originally Posted by Bikie John (Post 84484)
Just to add a little snippet to Pete's comments about using the Exposure and Blacks sliders to optimise the histogram:

If you press the Alt key (for Windoze, not sure what the Mac equivalent is) while adjusting the slider the image display changes to show highlight or shadow clipping as appropriate. This means you can see which areas are going to block or blow as you pull them in. Hard to describe but much easier to see. It also works for (highlight) Recovery but appears not to for Fill Light.

Ciao ... John

Doh, I just realised I forgot to mention this tweak, but you beat me to it! Well spotted John, Thanks :)

Any other contributions of smart tricks and tweaks for Photoshop are most welcome everyone..

Pete

Coming next: Sharpening :eek:


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