Channels & Masks Lesson 10: Using Calculations in Photoshop

It’s Friday, but seriously, deeple, get your entertainment and education at the same time as you enjoy this video which I pilfered for your enjoyment from the companion DVD of Deke’s Photoshop CS4 Channels & Masks One-on-One book.

In this lesson, Deke introduces you to the Calculations command which can be a little tricky, but oh-so-very useful and important to understand. As Deke notes:

Now I won’t sugarcoat it, Calculations is not easy—in fact, it might be Photoshop’s single most difficult feature to master. But it is the command that’s going to increase the quality of your masks.

When you’re done, you can return to your less edifying Friday festivities. Happy Weekending, Deeps.

Next entry:Something Just Totally Inspirational

Previous entry:Martini Hour 011, In Which Colleen Lures Back John and Russell—with Olives!

  • Removing/Disabling not common file extensions!

    Hey Deke!

    I’m sorry this here is not exactly on the topic but is Photoshop related! I didn’t know where else or who else to ask, and since you are the Photoshop guru I would really appreciate if you can help me here!


    Every time I have to save a file in Photoshop there are hundreds of extension, most of which I don’t EVER use! I want to make it easy to find the ones I use the most and removing the rest. So what I did is I went to Photoshop folder:

    C:Program FilesAdobeAdobe Photoshop CS4Plug-insFile Formats

    and deleted all the extensions inside BESIDES:  Bmp.8bi , Gif.8bi and Png.8bi

    I want BMP, GIF and PNG to be able to save as them.

    Now when I go to Photoshop to save an image there are fewer extensions but still there are many that I never use. How do I remove them so Photoshop don’t load and show them up?

    All I need is:







    I’ve marked with red the ones I want to REMOVE.




  • Not everything’s a plug-in

    Much of Photoshop is extensible, but most of the features reside inside the core program file, which is why it’s several MB in size.

    EPS, TIFF, and PICT (sadly on that last one) are hard-wired into the program and cannot be removed. (Or, at least, I don’t know how without harming the integrity of the program.)

  • Thanks Deke!

    I see. So I guess I’d just leave the way I have it right now. Thanks again for your answer. I appreciate it!


  • My Eternal Huzzahs Will Go To…

    ...the individual or individuals who remove from this otherwise stellar blog the b&w photos of the panting dog with the pierced tongue. The photograph is as disturbing as the art of Eyvind Earle.

    Also, I think I’m going to change my vote from four months ago on Deke’s fate FROM Smart Objects TO Blending Modes.

    So let it be written, so let it be done…


    “Thanks again, for another day full of something that I

    just can’t put my finger on.”—Kim Knoche

  • Issue with indesign one on one lesosn 2 HELP!

    Hey there, just having a slight issue with the Professor Shenbop task in lesson 2 of the One on One book.

    I have made the circle ready to receive text and have pasted the text on the top line. Everything works fine EXCEPT I get these weird red lines off to the top right of my page after I have pasted the text. I thought I had incorrectly snipped the red circle but not so, When I flip the text vertical the red lines flip as well.

    Help what am I doing wrong?

  • haha…i had the same problem

    ...then i found out the word “Shenbop” isn’t in my document’s dictionary! InDesign likes to underline misspelled words with red. If you add the word to your dictionary via spell check (ctrl + i), it will disappear!

  • Change in CS4 - Preview - P

    I just finished the CS4 Adjustments lesson on Lynda - went to PS to try it out and I seem to have discovered something troubling. At least to me. Hopped into a curves panel, whoosed around the sliders and ...there is no Preview check box. Hence no un-preview. And no P key shortcut. I can toggle the layer visibility, but that is a mouse move, and I can find no keyboard shortcut for toggling vis.

    I tried Shadow/Highlight and my trusty P shortcut still works. Whew. Am I missing something? Will I have to change? I am not so good at that.

  • Disable dynamic spelling

    Another option you have is to disable dynamic spelling. To temporarily disable InDesign’s helpful squiggles, choose Edit→Spelling→Dynamic Spelling. A check next to it means it’s turned on; nothing means it’s turned off. To have Dynamic Spelling turned off by default on any new documents, go to the Preferences, then Spelling, and make sure the check box by Enable Dynamic Spelling is not checked.

  • shenbop to the rescue!

    Thanks, trying it out now!

  • All good!

    Thanks for the suggestions, you were both right and the problem has gone away!


Be the first to drop some wisdom...