I have a problem.
V1 & V2 are photographs of the same page of a late 18thC bible taken 8 minutes apart.
V4 is the grey card picture taken to set the custom White Balance for the session - 5 minutes before.
Interestingly the difference is not obvious on the uploaded version though the originals show V1 with a blue cast. Also V3, whilst a little lighter has the same apparrent WB as V2.
I have now looked at the histograms for the 2 pictures.
All pictures had a Temperature setting of 4895 and Tint +3.
To get V1's histogram to match V2's I have to adjust Temperature to 5400 and Tint to +4.
All photgraphs were taken as raw images.
The white balance was set and the camera's settings saved.
I changed the aperture to f8.0 for the V1, but as I didn't resave the settings it reverted to f4.0 unnoticed by me (slap wrist) before the next picture - V3 - was taken - 2 minutes after V1.
V1 f8.0 1/6s ISO 200
V2 f4.0 1/40s ISO 200
V3 f4.0 1/25s ISO 200
V4 f4.0 1/10s ISO 200 - Grey Card
All photographed in natural reflected light with no flash. There is no chance that I could have cast a shaddow over any part of the subject.
Why is there such an apparrent difference in the colour of V1 to the rest.
I really would appreciate someone enlightening me on the likely cause.
Thanks very much,
Specialist and abstract
Flash and lighting