Thursday, April 30, 2009

Alternate Viewing Realities: Variable Gamma Values

Okay, first off: I'm not about to get into a who's better Mac-Or-PC tiff with Anybody (I've had both and used both). Frankly I'd rather argue religion, politics, AND sex before getting into that. There's no rights or wrongs here, just differences. So if you care to comment, leave your platform outside the box.

While researching separate issues for the Photoshop Tips blog, though, I happened to run across an answer for a question I had not yet fully formulated. Which is: Why is there such a range of contrast among Internet images? While each blog tends to have a consistent range of picture quality, some blogs images may appear to some of us as overly light or overly dark (and, like Goldilocks, some are 'just right').

Apparently we can thank something called GAMMA VALUES. From the Photoshop 'Help' files: "The gamma value of a computer monitor affects how light or dark an image looks in a web browser. Because Windows systems use a gamma of 2.2, images look darker on Windows than on Mac OS systems, which are normally set to a gamma of 1.8."

Sample of what an image might look like created on a PC (but viewed on a Mac)...

...vs. how it might appear created on a Mac (but viewed on a PC).

(image: Golden Wings Deaux, oil, 36" x 36")

Depending on whether you are viewing form a Mac or a PC, one of these images will likely appear 'more correct' than another.

For an easy tutorial on how to 'average out' your photos for the masses, see today's Photoshop Tip on Adjusting Gamma.


  1. Thanks for the education...I have a lot to learn.

  2. Thanks for the tutorial R I don't have Photoshop but sometimes I think I need it.... lol! I do, however, love my Mac..... but I'll keep my big Mac mouth shut! LOL!

  3. Wow, thank you for that. I'm not sure what I will do with the info but the difference in the contrast is striking! Thanks for all your photoshop help.

  4. Wow!!! what a how were you able to create these images? You must have access to both.

  5. Ahhh. another good explanation. thank you, R!

  6. Hi Michelle, there's Always more to learn... this is a new one for me! I don't know why I never heard of it before.

    Manon, Glad you love your Mac! I say love and learn with whatever you've got!

    Hi Dana, I'm not quite sure how this will change my approach, either. I'm still mulling it over...

    Hi Sheila, to create the samples, mostly I used Image Ready (which is a small separate program bundled with Photoshop), and I used followed the steps shown at the Tips blog.

    Thanks Liz, I was trying to keep it short. Still trying to get my own head around it!

  7. Amazing...
    Good grief... there is just so much to learn... I guess what you are saying is that the way I see an image on my computer may be different than how someone else with a different computer monitor sees it.
    Do I understand that if we "even out the image's gamma value" before sending it up our out or...... it would be seen the same on all monitors??????

  8. Once again, you come to the rescue.
    I was thinking about how works are judged online...No one tells you what computer they are using to view images. Are we to assume they use Macs or PC? So this might help!?
    So much to absorb....
    thanks as always,R!

  9. Marian, I'm with you! As soon as I think I’ve got a grasp of a situation, along comes a whole 'nother batch ok knowledge to process.
    And sadly, no; your image will still look different on any given monitor in our standard .JPG's. The exception being the PNG format, which is 'read' differently by Macs and PC's, so this file format may be preferable and present 'less' variations. Still, visit your average computer store and just look at the monitors on display-- you'll see a lot of variation.

    What an excellent point!! I never considered that. Although I don't think any assumptions can be made, perhaps it wouldn't hurt to inquire in the case of online judging, or to see if they would accept a .PNG.

  10. Your work is just outstanding...You are an inspiration for me..Not only drawing but there is lot of information I can get here on this blog...:)


Thank you for your kind comments! They always make my day.