Photoshop same image - different colour

[oodya]

Hello,

I am wondering if someone can help please? I have an image that I have resized to A5 and attempting to print 4 on an A3. The problem that I am having is that when I place the exact same image across the Photoshop board, the brightness seems to be different (although it is exactly the same image).

I cannot show the complete image (due to copyright), but I have included the bottom section of the image (where the colour seems to be different). Is it me, or does the second image 'green on bottom' look lighter that the others.

This then seems to show when I print the files and is causing me problems.

I am using Adobe Photoshop CS6.

Any ideas?





Thank you in advance.

 

[IamSam]

Did you use the Info Panel to test your theory?

 

[IamSam]

In testing the exact same pixel from both images.......


The top image was R:158 G:210 B:196

The bottom image was R:157 G:208 B:192

At least in the screen shots, there is very little difference in coloration.

 

[oodya]

Thank you for checking - when visually looking - do they look the same to you?

I am printing some work for a customer and cannot figure out why the colours are printing differently. On screen they look different and when printing they are definitely different (although the image that I am using is exactly the same).

 

[oodya]

It also looks different when I place the image a few times on an Illustrator artboard.

 

[IamSam]

when visually looking - do they look the same to you?

Yes.............but these are small sectioned screen shots. It might look different if I was looking at the whole image. (not asking for you to post it, just explaining)

I am printing some work for a customer and cannot figure out why the colours are printing differently. On screen they look different and when printing they are definitely different (although the image that I am using is exactly the same).

This is out of my area of knowledge. Too many variables to consider. Often times the culprit is monitor calibration.

 

[oodya]

Thank you for your reply.

 

[IamSam]

Your welcome. Be patient, someone with more knowledge on this subject will come along to help you out in this thread.

 

[thebestcpu]

Hi oodya
The mathematical difference between the two images is miniscule. I aligned both images within photoshop and blended with difference. There are a few bit differences yet on average, the difference in luminosity is 0.34 bits with a variance of .54 bits.
If the actual image is not changed and your are just placing 4 of the same image in a larger canvas with the same dpi, there actually should be zero bits difference yet that is a different matter.

There can be actual and perceived differences due to other factors.

If the surrounding background when viewing is different (surrounded by white vs surrounded by black will perceived to be different. So even the display style in surround areas can make a difference.

If viewing on different monitors, they can look different due to different monitor settings, color gamut, and luminosity settings (e.g. calibration and profiling)

No exactly the same color management in handling the images can also make a difference. Are you consistently using the same color space wtih the images tagged wtih the color space icc profile? Do you have the color settings in both Photoshop and Illustrator set up the same way. That too can make a large difference.

If you actually resized the image where the number of pixels in the image have changed (the images was re-rendered), then there can be small changes from that as well (yet quite small changes).

Soft proofing turned on or not also makes a difference.

It could be any one or a combination of the above. I am pretty sure it could be tracked down step by step if important.

But bottom line, the two sRGB sample you provided while having some very small differences, is not the source of any actual difference in luminosity. So the issue lies elsewhere.
Hope that helps and you can always ask more questions.
John Wheeler