Variochromat

Procedure

Monitors

Photograph: Kai Sandner

 

Variochromat prints

The Variochromat is essentially a digitally driven enlarger, not a conventional electronic printer.
Photographs produced with the Variochromat system are individually printed, effectively by hand, rather than being mass produced.
Bringing the craft skills of conventional photographic printing to the world of digital imaging.

Variochromat prints can be every bit as good as analogue hand prints,
often better!

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Working with digital monochrome

Traditionally technicians would determine how the final print from a negative looked, hopefully matching the photographer's expectations.
Now much of that control can be handed back to the photographer.

However, with just a few mouse clicks, it's possible to ruin an image in seconds.
A picture, which looks stunning on a monitor, can be rather less than stunning when it's printed!

In the digital domain it's the lab's job to reproduce the photographer's images as faithfully as possible.
This means both lab and photographer need a standard to work to

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Resolution and colour depth

The Variochromat exposes with 6400x4800 pixels (around. 30,7 million pixels!)
It uses a depth of 8 bits (256 tonal values).
To save reduce file size we recommend converting RGB files to greyscale.
There are several ways to do this, the simplest being to change to greyscale mode in the "Image" menu.
Other methods, such as the "Channel Mixer" within the "New Adjustment Layer" option in the "Layers" menu allow selective density for each colour.
If you are unsure, send us your RGB file, and we will convert to greyscale as we consider most appropriate for your image.

Very few digital cameras can achieve 30 Megapixel resolution, but
for a good quality print it's quite sufficient to use around a quarter of this resolution.
There is no need to interpolate the data. This will just increase the file size with no improvement in quality.
If you are sending a digital camera file just send us the image at the original resolution and we will adjust as necessary.

If you are scanning film the following table gives our standard format resolutions:

20 x 30 cm ~ 8 x 12": 4267 x 6400 26 Mb
30 x 40 cm ~ 12 x 16": 4800 x 6400 29 Mb
40 x 50 cm ~ 16 x 20": 4800 x 6000 29 Mb
50 x 65 cm ~ 20 x 25": 4800 x 6400 29 Mb
50 x 75 cm ~ 20 x 30": 4267 x 6400 26 Mb

The file sizes are for greyscale scans.
We would recommend against using "lossy" compression, such as Jpeg, unless you are sending us data online and have a slow connection.
We would prefer Tiff files.
If you do use Jpeg or J2K use the maximum or highest quality level possible.
This will reduce the artifacts introduced into the file.
If you make any adjustments to your image remember that each time you save it back to disk as a Jpeg more degradation is introduced.
However Tiffs with LZW compression are fine, with no reduction in quality.

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Histograms or levels

The "Levels" adjustment (Ctrl + L or Apple + L in Photoshop) displays a "Histogram" - a graph showing the proportion of different values of your image across the tonal range.
Of course this will vary according to whether your image is high or low key etc, but in general the full tonal range should be covered. If there are gaps in the histogram, it indicates that the file is missing those tonal values - the print will be less brilliant and detailed.
This often happens when images have been over manipulated, or repeatedly saved as Jpeg's. It should be emphasized that every procedure in Photoshop will increase this "gappiness" (Try a few "before and after" histograms - you may be surprised!)
We can correct for small gaps, but if 20% or more of the tonal range is missing the file will probably not print well.
It's not possible to interpolate huge gaps - no algorithm can create information, which wasn't there to start with.
If possible make sure, when taking a digital picture or scanning, that the maximum range of tonal values is covered.

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Aspect ratio

If your image is different in aspect ratio (shape) to the chosen print format we will not normally crop.
We will print with a white border on one side.
Alternatively you may wish to crop the image to fit a given print format.
(Aspect ratio = Width : Length)

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Banding

Banding between adjacent tonal areas, which should be normally smooth, can have several causes, namely:

• The scanner or the digital camera was not capable of recording the contrast range in the picture.
• Tonal corrections with software have been overdone or soft focus filters have been applied.
• Digital cameras have been improved hugely as far as resolution goes, but they still have trouble reproducing huge differences in brightness.

This shows worst on smoothly graded areas such as skies, and skin tones.
Even if a file looks "pixely" - don't try correcting it with a soft filter.
Brightness and contrast should be adjusted before scanning, if necessary, but only small corrections are usually needed.

Although banding doesn't show on most monitors as much as on the final print, thankfully this is not a common problem.

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Sharpness

Enlarge your file to the scale 1:1 on the monitor (Assuming the image size is the same as the desired print).
If the image doesn't look sharp, it will probably not print well. Prints are very revealing!

If you want to sharpen the picture you can use the "unsharp masking" filter, but do be sure that the image doesn't start breaking up tonally, or "fizzing"!
Images will sometimes benefit from local sharpening - make a selection around highly detailed areas and just apply the filter to those. Unsharp masking can improve the overall sharpness of a picture if it's used with discretion.

If you need any further information or help do hesitate to call 01892 615715.

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