Luminance vs Brightness

[David_H_...@adobeforums.com]

I am trying to calibrate my screen and the documents I have (instructions, books, web sites) use both the terms 'luminance' and 'brightness'. Can anyone tell me the difference between the two? Are they the same? The instructions I have tell me I should have a 'luminance' of 100-120 cd/m2 but my monitor only adjusts the 'brightness'. Thanks!

[Denn...@adobeforums.com]

For the practical purpose you are faced with, they are one and the same. For LCDs, the "luminance" level will usually be very high and you will need to bring it down using the monitor's Brightness control. It is not uncommon to find LCDs that are so bright that even a Brightness of 0 will produce a Luminance reading of higher than 120 cd/m2.

[David_H_...@adobeforums.com]

Thanks Dennis! I very much appreciate your response. (I changed the 'Brightness' from 75 to 60 and it appeared not to make any difference. I'll try lowering it even more.)

[David_H_...@adobeforums.com]

I changed the brightness to '0' just to see, but the screen was way too dark. I reset it for 25 and its still pretty dull. My comfort level is probably around 60 but it sounds from your e-mail that that would put me way over 100-120. How do I know what 100-120 cd/m2 is?

[Denn...@adobeforums.com]

What calibrator/profiling device are you using? Normally the software will give you a reading from a white patch and you can tell from that.

[David_H_...@adobeforums.com]

I'm using Spyder 3 Pro. I followed all the instructions (I thought!) but haven't seen a white patch appear. I'll look at my instructions and see if I missed it somewhere. I'll get back on the forum if I need to. Thanks.

[Denn...@adobeforums.com]

If I remember correctly, you need the Spyder 3 Elite for it to give you the luminance value. Kind of dumb but I believe I ran into that a while back with another poster.

If you mention the make and model of your monitor, maybe someone can mention the Brightness setting they use to get close to the 100-120 luminance. The recommended luminance can also vary somewhat depending on your working environment illumination. The brighter your surroundings are, the brighter the monitor can be in general terms.

Where an overly bright monitor will impact you the most is with your matching of prints. The brighter the monitor, the more disappointing your prints will look in comparison.

[Free...@adobeforums.com]

According to the data sheet, the Spyder3pro does not allow you to set luminance. Gamma and temperature yes, but luminance no. This is a major shortcoming, considering that recommended luminance values are around 100 - 120 cd/m², but most LCDs are natively up in the 300's. Editing images on a monitor at 300 cd/m² is a recipe for disaster, unless you're sitting out in the sunlight.

One possible/future upgrade option is to purchase Color Eyes Display Pro at $175 (software only). This will work happily with the Spyder3 puck, so you can keep that.

<http://www.integrated-color.com/cedpro/coloreyesdisplay.html>

[Wolf_...@adobeforums.com]

Eric Chan discusses his "poor man's" technique for setting the monitor luminance at this site: <http://people.csail.mit.edu/ericchan/dp/Epson3800/printworkflow.html>

[David_H_...@adobeforums.com]

Thanks Wolf. I'll try the link.

(Hi Freeagent. I had to hunt for the Color Eyes Display Pro you referred to in the other thread. So, here's where it is! Having spent a chunk on the Spyder 3Pro (and all the other gadgets, hardware and software I'm purchasing) I'm trying to find economic means of addressing some of these issues. I should have just bought the Elite! Lessons learned.)

[Free...@adobeforums.com]

You're welcome, David. :-)

BTW I read Eric Chan's piece, and it's excellent. For those who don't frequent the ACR forum, he's on the ACR engineering team.