Problems with dark Artifacts on images when viewed on PC screens???

Question

I have a very urgent problem concerning Adobe Photoshop CS3, my Apple Cinema 20 inch Display and my SpyderPro2 on my Mac Pro Intel Dual Core Xeon 2x 2.66GHz.
I have been using the Spyder for some years now, but recently I have been having big problems with the results. I only use Photoshop CS3 to enhance digital products images.
I have a major contract with a jewellery company in London, where I clean up digital photos. Images that I have lightened up to look great on my Cinema Display have been reported by my client to look pretty dark on their PC's in their offices.
Some of these images show lines and grubby patches??? To check this I opened files in Photoshop and moved the levels 'black' slider down quite some way, and did see evidence of what the client could see at their end? It seems that when I have used a faded eraser brush it leaves a light patch in between the shadows of the jewellery. This shouldn't be visible to the naked eye though?
I must point out that when I use the eyedropper tool on images, to read the amount of grey or colour in the white areas around the peices, I am shown values of 1,2 or 4 maximum in the CMYK values. 4 percent out of 100 is nothing and should not be visible to the naked eye?
How is it that my clients PC's can see dark shadows and where my eraser brush has rubbed out???
I have tried many re-calibrations and also tested all of my older calibrations dating back a few years. I have also tested the same faulty images on Intel iMac's, an eMac, and a few PC's. On the iMac's I can just about make out the artefacts that my client can see, but nothing that I would deem as unacceptable.
I am at a loss as to the fault, but It may be the Spyder2 Pro's inability to calibrate my Apple Cinema display properly? I may lose my contract which I cannot afford to do, and I simply have to find the cause ASAP.
I have my Mac's in my office apartment next to two bay windows. I have vertical blinds there. When calibrating I have always turned off all the lights and pulled the blinds right back so that only the light from the two large window doors is coming in.
For graphic design the calibrations seemed to be okay for quite some time, but recently it is getting harder to achieve good results with the Spyder? This could affect all of my workflow which is very serious. But I must stress that overall the Spyder results are not terrible. I can see good colours and dark levels and in general across all of my calibrated profiles, the jewellery looks acceptable on my Cinema Display?
I did say to my clients that they should calibrate their PC screen properly but their offices have many Screens and they all show the same artefacts (some much worse than others)? I know that PC Screens are darker than Mac's but a 4% grey should not be visible????
As these are a web company the images will be seen by PC users around the world and most of these will have no calibration on their screens. What can be done to prevent this and what is the cause of this? I can't possible please everyone, but as a creative professional I have to be 100% certain that my workflow is at its best.
I need urgent help to solve this or loose valuable business? I hope that you are able to help solve this mystery. Could this possibly be something with Photoshop?
I have just purchased the new Spyder3 Pro which I hope will give perfect results but I have to find out what the cause of this is. If some of the fault lies with the client, I can charge these for all the testing and calibrating I have done.
Kind regards,
Jason Conway
ideo-sync - inspired design.

Answer 1

Thanks for all your comments and so quickly.
To be clearer, I am not working in CMYK for image enhancing at all, but windows RGB in photoshop, which is darker than working CMYK or Monitor RGB. I just use the CMYK colour scale in the photoshop colour picker window to see what values are around the object.
its not 4 across all four but on average C4, M2, Y1, K0.
When saving in save for web the images look fine on my screen, pretty much the same as the photoshop tiff file.
Each image has adobe RGB 1998 embedded when saved as a tiff file.
The client looks on internet explorer 7 on their PC's and also within Photoshop.
Colour settings within photoshop are using MacUser magazine's recommended setting from 2006: RGB: Adobe RGB 1998, CMYK: Euroscale Coated V2, Grey: Generic Grey, SPOT: 20% dot gain. Engine: Apple CMM, Intent: Relative Colorimetric. Also Black point compensation and User Dither are checked.
Also the monitor calibration is set at 6500 at 2.2 gamma.
To be clearer about the dark shadowing and the artefacts. When using levels I click on a shadow point to remove all but a slight shadow. Then I sometimes need to use the faded eraser to clean up or lessen the shadow. The image looks fine on my screen, but in the levels window I drag the black pointer about a third of the was across the screen to simulate what the client is seeing on their screen. This is quite a long way to drag the slider. I can sometime see the edges of the image, or white holes where the eraser has been. The lines are areas around the object that have been rubbed out a bit.
I agree that colour values will show on a screen, but the effect of the shadow should be smooth and not clearly visible with an edge?
http://www.ideo-sync.co.uk/p110741.jpg
also p110741.tif
I have uploaded the layered tiff file and the web jpeg to my server, so you can hopefully see something odd?
If there is a problem with my cinema display at least its under warranty, and the new Spyder3 pro should help when it arrives in a few days time.
Hopefully I can pinpoint the exact cause to this and take steps to stop this ever happening again. I am very grateful for your advice and help.
Kind regards,
Jason.