Black level differences

chrisgeary

chrisgeary

Suspended / Banned
Messages
758
Edit My Images
Yes
Monitors seem to display black level differently... my calibrated Dell 2209WA leads me to believe I have a nice image, but then I look at it on my mac (also calibrated allegedly) or my PC at work and the black level has dropped significantly resulting in really dark areas that should contain shadow detail. Exporting from Lightroom to jpg also seems to drop the black level a bit as well.

I'm working in sRGB. My monitors are as well. Am I doing something or missing something in Lightroom?
 
If you can't trust your monitor(s) then maybe you can put some faith in the histogram and the shadow clipping warnings. Personally I am guided at least as much by the histogram as the image itself when making adjustments to black and white points (blacks and exposure) in Lightroom. So long as I know the data in my image file is "correct" then displaying that image data accurately is a separate issue. Certainly there is no point adjusting a monitor to compensate for duff image data, so get the data right first (aided by the histogram and clipping warnings) and then fix the monitor display.

If you want a simple gauge of the monitor's calibration for black and white points then look at a step wedge to make sure you can distinguish the individual levels from black through white. An example can be found here - http://a.img-dpreview.com/reviews/common/grayscale.gif

If you want a more detailed view of the greyscale performance then try the free software here - http://tireal.com/index.php?page=etft
 
Thanks Tim. I'd forgotten about the black clipping end of the histogram. Of course removing shadow clipping doesn't necessarily make the image "right". Thing is, the monitor I'm using now is spyder3 calibrated. According to the wedge, I can see all variations except Y and Z which basically look the same to me.

Still, if I have produced an image that looks as I want it in lightroom, why does the black level change when I export it to jpg, even at 100% quality? Do I need to change my colour space?
 
What happens if you re-import the JPEG file output from Lightroom and then compare it to the original file, with adjustments, within the same copy of Lightroom on the same monitor? Do the files look tonally different when viewed side by side?

p.s. Lightroom operates in the Pro Photo RGB colour space, converting to sRGB only when you output the final file. That may account for tiny shifts in colour, I guess, but I don't see why black level should change from 0,0,0 in any colour space of file type.
 
You must log in or register to reply here.
Back
Top