More calibration questions

[Julia_Miller@adobeforums.com]

Hi. Have read the post below about calibrating the LCD screen w/o a spyder.

Let me begin by saying I'm working on a PowerBook G4, purchased in mid-2003 (if it makes a difference).

I know I need to get a hardware calibration system, HOWEVER ... I would like to try an eyeball calibration for now. I will look at the sources/articles you've all previously mentioned.

Still, some questions:
1) Why is the Apple calibration wizard not offering the tristimulus values that Adobe Gamma does? (Someone mentioned using Adobe Gamma on another thread ... is that on an OSX machine? I use on my PC, have not been able to figure out using it on this computer.)

2) Can someone please explain the issue of gamma to me.
a. WHY are PC and Mac gammas different?
b. If I am designing for the web, shouldn't I be using a gamma of 2.2, so that people viewing my page on a PC (90% of the world, unfortunately) will see the images as I intend?
I designed a web page in a design course at school (on a Mac) ... when I got home and viewed the page in IE on my husband's PC, I was really upset with what I saw. I had to keep explaining to him and everyone who saw the page that the images really weren't that dark and that the colors were all wrong.

When I did the opposite -- design a page on the PC, post it to the web and then view on a Mac, the look was fine.

Thanks in advance for your patience and your advice.

[Tim_Lookingbill@adobeforums.com]

Apple for some reason designed their eyeball calibrator to read factory measured tristimulus numbers written into the EDID chip on some monitors mainly Apple's lowend LCD's and other CRT's like mine.

PC users use Adobe Gamma or BestView, a new eyeball calibrator for PC's mentioned by others in these forums. There's plenty of instructions on how to use Adobe Gamma for PC's in the links provided in these forums.

I use SuperCal because it gives me consistant neutrals from black to white. I can set my white point to whatever and choose from a variety of tristimulus for better accuracy. It's better than any eyeball calibrator I've ever used.

With color management what you set your monitor's gamma to doesn't matter because it's adjusted in tagged files viewed in CM apps like PS, anyway. The web standard everyone, even Apple, recommends is 2.2 because it reduces the complexity for those that may use nonCM apps like web and consumer grade photo browsers.

The reason your web page looked dark is because you didn't convert from your, I'm assuming, 1.8 (lighter) Mac gamma to 2.2 sRGB-the color space of the web. You edited your image in a comparatively lighter viewing space making it darker than it needed to be. It then seemed even more darker when viewed in the darker 2.2 gamma space.

Really you can set your monitor profile to any gamma you want as long as you convert to your destination space (the web? CMYK?) in PS. Some set their displays to odd numbers like 2.0 or 1.5 to get their monitors to show all 256 levels of gray in a 21step grayramp like this one:

<http://www.inkjetmall.com/store/workflow/21stepNew.jpg>

If you just set it to 2.2 on some monitors like mine, certain number of gray levels go to black causing the user to lighten shadow detail in images while in AdobeRGB 2.2 gamma working space that may not need editing.