The Problem of Colour Consistency in Photographic Reprints

The Problem

The resolution, contrast & colour capabilities of conventional 35 mm film are very good but prints are often returned from film processing companies with an unexpected hue, saturation or brightness shift. It is disappointing when one shoots a photograph particularly to get a particular colour effect to then find it distorted or homogenised out in the print. Getting reprints that don't match the originals is also frustrating.

The following 4 pictures are scans of prints from the same negative. They were scanned on the same scanner with the same settings (other than the second one which is a reconstruction because I gave it away long before writing this page). The difference in colour is from the photographic printing.

Deep blue, high contrast. Blue with pinkish highlights, reduced contrast. Blue, reduced contrast. Dark grey with pinkish highlights, high contast.
Original (Matt, Kodak) Reprint (Gloss, Kodak) Reprint (Matt, Kodak) Enlargement (Matt, Jessops)

That photograph might have been particularly bad in its reproduction colour consistency because there were few clues in it for the printer, whether automatic or by a human operator, to deduce the intended colour to adjust to. I took it facing the sun deliberately to get the silhouette, colour cast & high contrast effect very different from a standard appearance. The distinct colouration also makes any variations obvious.

Why the printers have to adjust colours at all I don't know. Explanations I have had from print companies include: compensating for the variations in the orange base colour of the negative film (but that could be calibrated from interframe gaps); differences in the print film stock & developer chemicals used (but that should be calibrated for when printing machines are set up); and trying to improve normal poor snap-shots.

It is the latter I am most inclined to believe. It was almost certainly what happened in the following case. I wanted the subtle sunset silhouetted behind the dead tree. The original print was printed as I intended, possibly because having a whole film processed and printed at once avoided special attention to that negative. However when I had it reprinted for a Christmas card by the same company at the same size with same paper finish, the brightness was raised so much that the sunset was almost totally whited out which wrecked the photograph. I reckon that the printer operator thought I had intended to photograph the surface detail of the tree not the sunset and so had raised the brightness to compensate for what they thought was an exposure setting mistake on my part.

Subtle sunset behind silhouetted tree. Whited out sky behind dark tree.
Original (Matt, Kodak) Reprint (Matt, Kodak)

Traditional Solutions

The traditional professional solution is, of course, to do ones own printing but darkroom processing is expensive and time consuming even for black & white with colour being even more difficult. Hopefully home computer printers will eventually solve that problem but affordable inkjet printers are not yet (early 2004) quite sufficient. They have sufficient resolution and almost sufficient colour depth but the consumables are expensive and the prints discolour far more rapidly than normal silver halide photographic prints.

The other common solution is to send the wrongly coloured photograph back to the printing company together with the negative, the original print (assuming it was not the original which was wrong!) and instructions to colour match the original. However, I don't like to do that as it hassles the poor printing staff, it takes extra time and it riskily puts all three copies of the picture in the same place where they can be lost or damaged at once.

An Easy Solution: Reprint the 35 mm Photograph as a Digital One

After buying a compact digital camera as more portable supplement to my SLR, I found that the same printing companies which had so much variation in colour for 35 mm prints were remarkable consistent in colour when making digital prints onto the same photographic paper. The consistency is not perfect but is a lot better.

The following example is from a digital camera. It was printed by three WWW based services (Photobox, Bonusprint & Kodak Ofoto) and two highstreet based ones (Boots & Jessops). The scene was a test still-life I assembled to have a variety of bright & subtle colours, flat & textured areas & extreme brightness variations (so it is not very artistic!):

Stilllife test photograph. Stilllife test photograph. Stilllife test photograph. Stilllife test photograph. Stilllife test photograph.
Photobox (Matt) Bonusprint (Gloss) Kodak (Gloss) Boots (Gloss) Jessops (Matt)

Similarly for a colour (& cropping & resolution) artificial test image I assembled in a drawing program:

Test card. Test card. Test card. Test card. Test card.
Photobox (Matt) Bonusprint (Gloss) Kodak (Gloss) Boots (Gloss) Jessops (Matt)

I reckon that the reason printer operators meddle less the colour of digital photographs is that many customers have seen their photographs on a computer screen or the LCD screen of their camera before sending them off to be printed & will complain if the prints look very different from what they have seen in advance. Alternatively it might be that the printing companies know that digital cameras used for snapshots normally have automatic white balance (colour correction) as well as automatic exposure so the printing process doesn't need to do it as well. Whatever the reason, it is good for people like me who want colour consistency.

Therefore a solution might be: scan in the print (with compensation for a gamma=2.2 display), adjust the colour if needed, save it as a JPEG image & send the file for printing pretending that it came from a digital camera instead of sending the negative. It does not require one to have a digital camera to do this as most high-street operators I've found will take images on CDs as an alternative to camera memory cards and on-line ones of course accept upload over the Internet. There is no need to even bother faking the EXIF data stuff that digital cameras embed in the image file to record camera settings - I've tried with & without the EXIF chunk and the results were identical.

If the scan is made using a good (high resolution with automatic dust removing) negative scanner and checked for damage (with damage repaired as necessary) then the digital reprint should be as good as an optical reprint. If one does not have a negative scanner then one can use a normal flatbed scanner to scan the photographs in which case there will be a slight reduction in sharpness because it will have gone through three optical stages (conventional printing, scanning & digital printing) between negative & print instead of one and because of the large grain size in film paper. The reduction is not drastic and probably will not be noticed by most people and be negligible other than on enlargements or with very fine lines in the scene. Furthermore, I have found that digital sharpening (consisting of an 'unsharp mask' followed by an 'edge preserving smooth' to undo the sharpening of grain in the flat areas) made even my finely detailed reprints from scans indistinguishable from reprints direct from negatives.


After first publishing this article, I tested the method on the original example photographs. Here are the results:

Deep blue, high contrast. Deep blue, high contrast. Deep blue, high contrast.
Original (Matt, Kodak) Digital Reprint (Matt, Photobox) Digital Reprint (Gloss, Boots)
Subtle sunset behind silhouetted tree. Subtle sunset behind silhouetted tree. Subtle sunset behind silhouetted tree.
Original (Matt, Kodak) Digital Reprint (Matt, Photobox) Digital Reprint (Gloss, Boots)

Although the colours & brightnesses are not identical to the originals, they were very close to it compared to the conventional reprints from the negatives.