Here is a sample I made of the problem with the oly 400/450 purple to blue problem:

http://www.dimensional.com/~gizmo42/d450/

Regards, Dave

-- David Threlkeld (gizmo42@dimensional.com), November 12, 1999

Answers

I have been reading a lot in the forums re the problems in recording blues/purples with digicams. I have a Minolta Dimage EX-1500 and also have experienced problems in this area.

Although there is little or nothing I can do on the camera itself to remedy the situation, I have managed to ameliorate the problem to a great extent using Adobe Photoshop (my version is 5.5) as follows. Incidentally, I starting applying these corrections with Kodak Photo CD scans when the files exhibit an unwanted cyan cast.

Opening the Hue/Saturation dialog box, I select Cyan in the Edit box and move the Hue slider to the right which I find corrects a great deal of the problem. (While I am there I also use the Saturation and Lightness sliders for additional corrections.) Occasionally I also will duplicate these corrections with the Blue selected in the Edit box.

Recently, I had need to photograph a Nikon camera body showing various lenses. These were shot outdoors using ambient lighting and automatic white balance. When I opened the files in Photoshop, the black of the camera body (and to a much smaller extent, the black of the lenses also) was heavily tinged with blue. I removed this blue contamination via the Hue/Saturation command, by decreasing the Saturation and Lightness for both the Cyan and Blue colors. The black of the camera body was completely restored.

This, of course, affects everything in the image, but since it is the camera/lens that was the subject and which filled the frame, this was no problem. Nevertheless, on those occasions when I open a Photo CD file and find it has a bluish cast (the operator is supposed to change the filters for different films, but I doubt that it is always done) , I apply these same operations to remove it and the results are excellent.

Other photographers will undoubtedly have their own methods for battling the blue/purple color problem (such as the Curves command, etc.) but this works well for me and it is fast. I think that trying to solve the problem from the digicam end is nigh onto impossible.

-- Albert Klee (aklee@fuse.net), November 12, 1999.