Over Exposure Correction

[DonH]

Greetings

Been lurking for a few weeks while I'm digesting Photoshop (not new to digital, just Photoshop - Why did I wait so long?), and also going through Katrins book.

While going through the example on correcting an over exposed image, it occurred to me that using an adjustment layer with a blend mode of multiply could accomplish the same results as the documented technique (select luminosity, create a layer, and set blend mode to color burn).

So, I tried it and pretty much got the same results. So my question is what the advantage of one technique over the other? Or is this an example of one of those 'half dozen different ways to get the same results in PS' things?

Great set of forums, by the by. Sites like this are a main reason I finally jumped on the PS bandwagon.

Thanks

Don

[Doug Nelson]

Selecting the luminosity only affects the brightest 50% of the pixels.

[jeaniesa]

My understanding is that selecting luminosity affects all of the pixels at whatever percent brightness the luminosity mask has. If you load the selection, then the marching ants only show the brightest 50% of the pixels, but they are not really a good indication as to what is really selected. (You can see this when you do a CTL/CMD-J to copy the selection to a new layer and turn off the layer underneath.)

Anyway, back to the original question, I don't think setting an adjustment layer to multiply blending mode does quite the same thing as the luminosity mask technique outlined in Katrin's book. Unless you mask the adjustment layer in some way, you are applying the adjustment equally to every pixel in the image.

The luminosity mask on the other hand is kind of like a "weighting system" in that the lighter areas of the image are affected more than the darker areas. In most cases this is preferable, esp. if the shadow areas are already fairly dark. If the darker tones are lacking in an image, then both techniques may look fairly similar in practice. But, if the image already has dark & rich shadow tones, then you'll definitely want to use the luminosity mask to tone down just the highlights.

Does that make any sense?

Jeanie

[DonH]

Thanks for the explanation of what's happening with the luminosity mask. It makes sense now as to why that technique would be preferrable.

Thanks again

Don

[Stephen M]

Originally posted by jeaniesa

The luminosity mask on the other hand is kind of like a "weighting system" in that the lighter areas of the image are affected more than the darker areas. In most cases this is preferable, esp. if the shadow areas are already fairly dark. If the darker tones are lacking in an image, then both techniques may look fairly similar in practice. But, if the image already has dark & rich shadow tones, then you'll definitely want to use the luminosity mask to tone down just the highlights.

http://members.ozemail.com.au/~binaryfx/ST_utilitymasks.html

Hi Jeanie, would you believe that there is a way to mask without making a 'hard' mask?

I have been using the layer option blend-if sliders since v4 when I first played with them. Sadly in v3 I wasted a lot of time learning about making masks, when blend-if can speed up many masking and tonal interaction situations.

So, how do you use multiply mode in say a levels adjustment layer to darken a light pic - without plugging the shadows?

Use the layer palette flyout menu to select layer blending options.

Using gray tonal blending and not separate channels, hold down opt/alt on the underlying shadow slider - and drag the half of the slider all the way over to the highlight position.

More on blend if:

http://members.ozemail.com.au/~binaryfx/PSTV_links.html#B

If we are lucky, Richard Lynch will read this post and grace us with one some thoughts about blend-if...Richard is the only other person I have met around the Photoshop traps who seems to rave about this feature as much as me. <g>


Sincerely,

Stephen Marsh.

[jeaniesa]

Originally posted by Stephen M
Hi Jeanie, would you believe that there is a way to mask without making a 'hard' mask?

Stephen, I would believe anything you say! I learned about the blend-if sliders a while back, and quickly went back to my "old way of doing things". Perhaps this time the info will stick!

Jeanie