Adobe Photoshop Training with Dan Margulis

Hi there, I'm following the posting about the yellow cast and how to deal with it as I have a load of images taken in a room that has yellow walls, orangy yellow wood floor, virtually yellow everything! I thought I would try Dan Margulis instructions:

Now, not being sure how to do this, I used calculations to apply one channel to the other and finished up with a new channel and am at a loss as to how to apply this new channel in any way to the original yellowy image! I tried 'apply image' but couldn't find an answer there either as my knowledge on channels is only just blossoming, would you be a kind soul and give instructions if you can spare a moment? I'm a new name to the list and haven't had much time to 'lurk' for a while, so if I'm being rude or something, you'll have to tell me! Thank you so much, Ruth

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The Apply Image command is only available when the channel that is being changed is the only one active. Open the RGB file with the yellow cast and proceed as follows:

1) Open the Channels palette and click to the right of the word "Blue." You are now seeing only the blue channel.

2) In the left-hand column of the palette (where you see an eyeball icon next to the Blue), click in the RGB row. Do NOT click in the right-hand part of the row. You should now see eyeball icons next to all four channels, but only the blue channel is highlighted, and although you can see the whole image, you will not be permitted to make any change to the red and green channels.

3) Image: Apply Image. Since Blue is the only active channel, that's automatically the target of your blend. Change Source: Channel from Blue to Green. Change Blending: to Lighten (probably currently reads Multiply). Change Opacity to 75%.

4) Since you're seeing the entire image, you can get an idea whether 75% is too little, too much, or just right. When you're happy with the Opacity number, click OK.

5) Don't forget to go back to the Channels palette and click on the right side of the RGB row, otherwise you still won't be able to touch the red and green channels.

Dan Margulis

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Hi Dan, many thanks for your help, I've just sat and worked through your instructions, that is one big help! I had written off a whole card full of photos but I can resuscitate them now, which will be good practice for me, many thanks for your time and patience, Ruth

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Ruth,

You mentioned your frustrating experience when you attempted to use Calculations for blending channels. Don't overlook its valuable potential for other uses. You can use the "new" channel in several other ways. Use Ctrl-A to select the entire channel, Ctrl-C to copy the selection, then Ctrl-V to paste the copied channel into a layer which can in turn be used to affect your image; for example, you can change the new layer's blending mode to Luminosity. Try it with various blending modes to see if any of them offer any usefulness for your applications. Or you can use Apply Image to grab the "new" channel and blend it with an existing channel. Or you can use the "new" channel as a channel mask, etc. Just don't give up on it because you experienced frustration with it the first time you tried it. Using it won't cause any damage to your computer, so try playing with it for awhile. Click "Mask" and select a channel that can be used to mask the effect. See what happens. If you try to find some detailed guide for the use of Calculations, it's going to be a long search. Few of my many Photoshop books offer any guidance for Calculations, leading me to believe that most authors don't know how to use this valuable tool. The best way to familiarize yourself with things like this is to just go ahead and try them out and see what happens.

If you're using a Mac instead of a PC, substitute the word "Command" for "Ctrl".

Howard Smith