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Nikon AF Nikkor 50mm f/1.8D

07/13/2004 12:51:00 PM · #1

How best to calibrate it so that I know that photos I process in Photoshop will look the same to others (with correctly calibrated monitors)?

It's a 19 inch Ilyama flatscreen.

David.C

07/13/2004 01:03:57 PM · #2

Set the temprature of your monitor to balance the lighting in the room you are in (does the same as the whitebalance on your camera), and then calibrate to a 2.2 gamma. This site is the easiest to follow, without sacrificing accuracy.

David

/edit: spelling :(

Message edited by author 2004-07-13 14:54:58.

07/13/2004 02:46:34 PM · #3

Thanks, I'll give it a go tomorrow when I'm more awake...
It's never good to do much that requires brain power when I've just eaten dinner and my body is either digesting or getting ready to switch off for the night!

Nikon AF Nikkor 50mm f/1.8D

07/14/2004 12:15:03 PM · #4

Thanks, I've followed it's guide to using Adobe Gamma and hoping I've done it correctly.

When setting the gamma using the sliders I had to slide them almost all the way to the left - hope that's correct.

Also, Adobe Gamma instructed me to set my contrast setting to maximum and I set my brightness to 80% (to make the centre square black but keep the outer one white). I was surprised to be told to have the contrast at 100% though??

I trusted that Adobe Gamma had correctly picked up the details about my monitor for the other page of the test wizard...

David.C

07/14/2004 02:28:24 PM · #5

Adjusting the contrast affects the dynamic range of the display, which is basicly the number of stops it can display at once. Lowering the contrast, lowers the number of stops that can be displayed. The instructions tell you to set your monitor at 100% contrast to not loose any of the dynamic range while the brightness is adjusted to set the black point (what value is black on your display). Most monitors can handle this, some can't.

I don't particularly care for Adobe Gamma's step-by-step because they assume the monitor can handle 100% gamma and do not take the next step and adjust the contrast to set the bright end back to where it needs to be. You can easily end up with a washed out display by doing this. This is easily overcome by having the calibration site I linked earlier open so you can see the black and white point scales on it -- adjust the brightness to get all four of the black-point boxes visible and contrast to get all four of the white-point boxes visible.

Perhaps an example will help. I am using the software that comes bundled with the driver for my ATI video card to make the adjustments since my monitor is old and needs the help. The monitor's controls for brightness and contrast are both set at 100%. The software also provides a curves display to make it easy to see what the adjustments are doing. One final note, the scales may not appear correctly on your display in the images that I say they look good on mine. This is fine, the final result is for my display, yours will look right when you do it.

This is my starting setup, I clicked the default setting button and opened Adobe Gamma, with the calibration page in the background.

At this point, contrast needs to be moved to its highest value.

You will no doubt notice the screen is severely washed out. This is also shown in the curves display by the left third of the color range being maxed-out in brightness. This will be fixed in a moment when we look at the white-point, but for now the black-point is what we are looking at and in adobe gamm I can not see the inner square and the last two of the scale on the web page are the same. The black-point is set by the brightness control, like this.

Now the black-point scale looks right, but the white-point is still washed out. This is the part Adobe gamma ignores. Since contrast sets the white point, I adjust it.

You will notice the brightness control raises the curve for the entire spectrum equally, the contrast control leaves the black-point alone and moves the white-point back to where it needs to be.

Now we move on to gamma, and the second reason I don't like Adobe gamma. Just as it assumes the monitor will look good at 100% contrast, but they also assume the monitor's controls will be all that is needed. Since both adobe gamma and the software I'm using are creating profiles for the display and only one profile can be used at once, if I use Adobe gamma to set the gamma it will ignore the brightness and contrast settings already made in the software I use.

Moving Adobe gamma's step-by-step forward to the gamma screen, this is where I am at. If I click on the slider to set the gamma in Adobe gamma it will throw away the profile created by the other software, so I won't be going any further with that. The setting of the gamma is fairly straight forward, just look move the slider (most accurate to click on it and use the arrow keys) until the inner box is the same shade as the outer box. It helps to step back a few feet and squint to kind of blur them together. I just take off my glasses, and they blur together quite nicely for me without my having to get out of my chair.

I don't need to adjust the gamma any. My monitor may be old and need all the help it can get in the brightness department, but the gamma is dead on every time once I set the black and white points.

Here is a screen shot to compare with the previous to demonstrate what adjusting gamma does in the curves display. I slid the control over to the left (lowering the gamma), and it bows the curve down. If I was to slide it to the right (raising the gamma) it would bow the curve upward.

As a final note, since adjusting gamma affects the black-point, it may be necessary to reset it after adjusting gamma. If that is the case, just readjust the brightness until it is correct again.

I hope this was helpful for you to know if you are following the steps properly. If it was, consider it a thank you for the kind comment you left on my Freedom II entry.

David
If it wasn't helpful just consider it to be me rambling on and ignore it. ;)

David.C

Nikon AF Nikkor 50mm f/1.8D

07/14/2004 02:33:19 PM · #6

It looks like I had issues capturing the screen shot with the contrast set so high, but the problem is not over any area that hides what I was talking about, so they should still work.

David

TechnoShroom

Canon EOS-30D

Canon EF 100mm f/2.8 USM Macro

07/14/2004 02:39:01 PM · #7

Originally posted by Kavey:

Also, Adobe Gamma instructed me to set my contrast setting to maximum and I set my brightness to 80% (to make the centre square black but keep the outer one white). I was surprised to be told to have the contrast at 100% though??

I trusted that Adobe Gamma had correctly picked up the details about my monitor for the other page of the test wizard...

That's the one part of Adobe Gamma you should ignore. You should set the black point outside of Adobe Gamma.

See the AIM website