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Author Topic: Calibrating and cd/m for Web  (Read 1082 times)

PBC

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Calibrating and cd/m for Web
« on: December 29, 2017, 12:21:59 PM »

Assume I have a good screen to print match and the monitor is set for 140 cd/m as part of the calibration and this works well well producing prints.   

As part of this set-up the cd/m was set by viewing the print brightness etc., but what do you base the cd/m on when editing for posting to the web or for digital viewing (projection, browsers, etc.)?

I assume I just leave it at 140 cd/m as you don’t know any of the set-ups that are going to be used for viewing - or is there a better ‘default’ to use?

Phil
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andrewrodney

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Re: Calibrating and cd/m for Web
« Reply #1 on: December 29, 2017, 01:51:30 PM »

You can’t control what others see on the web. It’s a crap shoot.
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Andrew Rodney
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PBC

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Re: Calibrating and cd/m for Web
« Reply #2 on: December 29, 2017, 03:00:45 PM »

Agree but wondering what the happy average is - or if there is a happy average?

Wouldn’t want to edit too bright or too dark for the average; so is it best to go for 150 cd/m - is there a rule of thumb for this?

For example - if submitting images for a competition where they will be using (assumed) calibrated monitors, what cd/m would you use for your monitor ?

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Tim Lookingbill

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Re: Calibrating and cd/m for Web
« Reply #3 on: December 29, 2017, 03:20:06 PM »

Anything white on a calibrated 150 cd/m display would be too intense for me with the ambient light I have next to my display.

I don't know what your lighting situation is so it's going to be impossible to give you advice that's applicable to your situation.

I'ld suggest you compare a printed 21 step gray ramp from black to white to the file on your display and check if you can see a difference between 250RGB next to 255RGB white and 5RGB next to 000RGB black. Both ends are going to cause your eyes to adapt to each other so you need to isolate each by zooming in full screen.

If you can't see a difference between 250RGB gray next to white you may need to reduce the brightness of your screen. I have mine set to 100cd/m and have a 100 watt equivalent LED daylight flood bulb pointed up to bounce off the ceiling to provide plenty of diffused soft light.

I have an additional equivalent wattage focused daylight flotube to get print matches to my display by moving the prints closer and farther away.
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andrewrodney

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Re: Calibrating and cd/m for Web
« Reply #4 on: December 29, 2017, 03:25:24 PM »

There is no happy average:



sRGB urban legend & myths Part 2


In this 17 minute video, I'll discuss some more sRGB misinformation and cover:
When to use sRGB and what to expect on the web and mobile devices
How sRGB doesn't insure a visual match without color management, how to check
The downsides of an all sRGB workflow
sRGB's color gamut vs. "professional" output devices
The future of sRGB and wide gamut display technology
Photo print labs that demand sRGB for output


High resolution: http://digitaldog.net/files/sRGBMythsPart2.mp4
Low resolution on YouTube: https://www.youtube.com/watch?v=WyvVUL1gWVs


Why are my prints too dark?
A video update to a written piece on subject from 2013
In this 24 minute video, I'll cover:
Are your prints really too dark?
Display calibration and WYSIWYG
Proper print viewing conditions
Trouble shooting to get a match
Avoiding kludges that don't solve the problem

High resolution: http://digitaldog.net/files/Why_are_my_prints_too_dark.mp4
Low resolution: https://youtu.be/iS6sjZmxjY4


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Andrew Rodney
Author “Color Management for Photographers"

PBC

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Re: Calibrating and cd/m for Web
« Reply #5 on: December 29, 2017, 04:01:57 PM »

Thanks Andrew - I did learn a lot from your original “prints too dark” article and will view the other video when I am back by my screen.

I may just be worrying about something that is not worth worrying about; in that I may edit my images too dark/too bright for web viewing - even if my prints look fine.   Or maybe having the screen/print working will already have my edits at optimum for the web - assuming the viewers are viewing with calibrated set-ups.

Phil
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xpatUSA

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Re: Calibrating and cd/m for Web
« Reply #6 on: January 05, 2018, 07:29:12 PM »

Assume I have a good screen to print match and the monitor is set for 140 cd/m as part of the calibration and this works well well producing prints.   

As part of this set-up the cd/m was set by viewing the print brightness etc., but what do you base the cd/m on when editing for posting to the web or for digital viewing (projection, browsers, etc.)?

I assume I just leave it at 140 cd/m as you don’t know any of the set-ups that are going to be used for viewing - or is there a better ‘default’ to use?

Phil

Phil, it's cd per square meter, not cd/m. Some write cd/m2 others write cd/m^2 . . .

Ted
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best regards,

Ted

Jack Hogan

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Re: Calibrating and cd/m for Web
« Reply #7 on: January 06, 2018, 12:31:07 PM »

Agree but wondering what the happy average is - or if there is a happy average?

It depends on ambient lighting.  sRGB assumes 80 cd/m^2, which works pretty well in my relatively dim home environment so that's what I typically profile to.

Jack
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andrewrodney

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Re: Calibrating and cd/m for Web
« Reply #8 on: January 06, 2018, 12:59:59 PM »

Not a lot of displays can natively produce 80 cd/m^2 and not long ago, even 110-120 (the so called and incorrect recommendation for all displays) could do so as well. IF you're not working with a high bit panel, not great.
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Andrew Rodney
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Doug Gray

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Re: Calibrating and cd/m for Web
« Reply #9 on: January 06, 2018, 02:37:39 PM »

Not a lot of displays can natively produce 80 cd/m^2 and not long ago, even 110-120 (the so called and incorrect recommendation for all displays) could do so as well. IF you're not working with a high bit panel, not great.

Yeah. LCD displays, with their nice appearance in well lit stores, changed everything. The old sRGB viewing luminance of 80 cd/m^2 is a reflection of typical CRT limitations over 20 years ago. And then Adobe RGB (1998) came along with a recommended viewing luminance of 160 cd/m^2. But the former produces a better match, luminance wise, with prints in a 250 Lux environment whereas the Adobe RGB is a good match for ICC recommended print viewing which is 500 Lux.

I use 100 cd/m^2 for both as well as other spaces like ProPhoto. I don't know anyone with a switchable monitor colorspace that uses 80 for sRGB work and then 160 for Adobe RGB work.  ;D
« Last Edit: January 06, 2018, 04:06:05 PM by Doug Gray »
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ericbowles

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Re: Calibrating and cd/m for Web
« Reply #10 on: January 28, 2018, 03:32:00 PM »

I think Phil has raised a good question.  Most viewed images are over the internet on social media or similar venues.  The devices are usually a laptop, smartphone, or tablet limited by sRGB color space.  In reality most of these devices can't display a substantial amount of sRGB.  The devices are not calibrated so the images are probably too bright and too blue.  So if that is the likely or intended audience, how might standards for color space and brightness change?

I have a Dell laptop less than 10 months old.  It's display covers 61% of sRGB and 45% of Adobe RGB.  The specs said nothing about monitor gamut - and you can see why.  My NEC PA241W is a wide gamut monitor that covers more than 100% of sRGB and Adobe RGB. 

I suspect that editing for a normal print then viewing on a general public device will mean the image is much brighter.  This probably gives it a little more pop and blows out some highlights.  A dark moody image is a little too bright.  Colors are a little too saturated with some lost detail in highly saturated areas, dark areas, and brightest areas.  But overall, 95% of the colors and tones are close enough that you don't see much of a problem unless you put it up against a wide gamut monitor.

I suggest that for web use, you might make images slightly darker (use 140 cd/m2 or slightly more) and slightly warmer to account for the device of others if you really want to be precise. 
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