Scan / print photos

It sounds so easy: The flatbed scanner reads in the unsuccessful holiday photo, the image editing program does the necessary corrections automatically, and the color inkjet ensures the brilliant expression. It would be nice, but the reality is usually different. How you still get appealing results, we show in c’t 7/99 on 27 pages.

Hanover, March 18, 1999 (dpi / uh). Angrily, Mathias N. (31) hurls a thin booklet with the words `MicroType Ocratek 1600 – Manual ‘into the corner of the room. In a friendly-optimistic tone, this work aims to introduce 20 pages in five languages ‚Äč‚Äčinto the secrets of scanning. But what the scanner delivers looks ghastly on the screen: Too dark, too blurry, too green. And the hope that the monitor is the cause of the evil, because he wrongly display the correct image, is not true. A test print – the first and only attempt – leads to another desperate act: The sheet flies, crumpled by an angry fist, in a high arc in the trash can …

Mathias N. is by no means alone in such experiences. The handling of pictures, scanners and color printers is unfortunately not quite as simple as the fresh and cheerful advertising would like to assume. And the generously enclosed handbooks raise more questions than they answer. Example complacent: With how much `dpi’ do I have to scan at all? What should the controller `Gamma’? What is the use of the adjuster for the miraculous’ white value ‘(motto: `knows nothing’)? Why does the cursed printer only deliver autumn gray in gray instead of colorful pictures? And why the hell do you have to ‘manage’ colors?

Well asked …

A few concise answers in a nutshell (c’t 7/99 on page 102ff): The scan resolution in dpi (dots per inch) depends on the intended use of the image and / or the image used Printer, the gamma control changes the contrasts in the image, and the miraculous white value determines what brightness the scanner registers as white. Color management is a process that takes into account and compensates for the device-specific differences in color processing.

Unpredictability and deceit of the pixel images are proverbial. Compared to the ‘electronic typewriter’ computer, working with pictures and photos proves to be considerably more demanding. And this overstrains the unskilled PC user despite the fact that it is so easy to handle dpi and gamma remotely.

The cause of the dilemma attributable only to the manufacturers of scanners and printers, but would be unfair. What some years ago still employed various professionals who had acquired their job-specific knowledge of long learning times, today’s computer can not easily take over, especially since the combination of PC, scanner, printer and software is so complex that you know something without -how does not come far. Unfortunately, there are only a few useful textbooks such as [1 | # lit1], which also bring the topic understandable to the uninitiated. Most of the available works are aimed primarily at the professional [2 | # lit2].

… and answered

Any questions in the haze of `scanning and printing’ are not exhaustive even in a thick book. The most important tricks, however, we reveal here – without claim to completeness. We attach much more importance to the practicality. With a few exceptions, we assume that a reasonably well-functioning system consisting of flatbed scanner and (color) printer is available. We therefore only devote ourselves to troubleshooting.


So a purchase decision should not go in this context; see the tests of cheap scanners [3 | # lit3] and ink printers [4, 5, 6 | # lit4]; the topic `Printing on the net’ has also been the subject of a c’t article [7 | # lit7]. The correct use of image processing programs can be read in [8 | # lit8]. Problems with widespread impact, to which we have already devoted ourselves in one of the last editions [9 | # lit9], will once again be a topic in this issue, albeit only briefly. Rather, this is about the right scanning, editing and printing.

Into the beachless?

How to read even difficult pictures with a standard device, what resolution brings the best result for what purpose, how to get slides and negatives in shape and what software options you better waive, that’s what the first article about scanning on page 102 is all about in c’t 7/99. Incidentally, there is still help for incompatibilities plagued PC users.

Even a decent picture profits here and there from changes [10 | # lit10]. Whether it’s about increasing the sharpness, softening, or avoiding what kind of retouching glitches