Printing a multi-layer process means combining two or three or four successive prints on the same paper. Each layer brings its chromatic contribution (a channel in CMYK Aquaprint), tonal contribution (a pigmented transfer in carbon), or opacity contribution (a gum pass). The final result is the sum of the stacked layers.
The challenge with these multi-layer processes is alignment. If you shift the second layer by a millimeter relative to the first, your final print has a visible defect — doubled edges, a colored edge cast, blurred tonal definition. By eye, with no reference, it's almost impossible to lay a transparency in the right place on an already-printed paper.
Registration marks solve this. Calibration Flow automatically adds a small graphic pattern to the corners of each negative. You stack two transparencies by aligning these marks, and the layers align by construction.
#How it works
When you turn on the Registration option in the export panel, four small patterns appear in the corners of the negative preview. These are the registration marks. Their shape is a multi-color mini diagram — Cyan, Magenta, Yellow — that overlap and create identifiable overlap zones.
You can choose the marks' appearance via a sub-mode:
- Color (default): bright colors, easy to see with the naked eye.
- Positive: light tones for processes in positive polarity.
- Negative: dark tones in standard negative.
- CMYK: a version where each channel is highlighted independently, useful for prepress separation workflows.
Whichever sub-mode you choose, the position and size of the marks are identical across all layers of the same print. That's the crucial point — if the mark is 12 mm from the corner on the first layer, it's 12 mm from the corner on the three others too.
When you stack two transparencies physically, you visually align the marks. If they overlap perfectly, your layers are aligned to within half a millimeter. If you see an offset, you physically reposition the second transparency until the marks merge.
#Why it matters
For CMYK four-color Aquaprint. Four successive layers — Yellow, Cyan, Magenta, Black in the recommended order. With each new layer, you lay the next transparency on the paper where the previous layers are already fixed. Without marks, you align by eye on the image itself, which is imprecise. With marks, you align on the marks alone, and you get precision on the order of half a millimeter.
For Deep Color carbon. Three transfers of pigmented gelatin — Cyan, Magenta, Yellow. Vision Picturale documents half-millimeter registration precision as the target for this process. The marks are the only realistic way to reach it.
For multi-pass gum bichromate. If you make a Monochrome Aquaprint in two or three successive passes (to build up the pigment), the marks let you lay the second and third pass exactly on the first. Without that, your density builds up unevenly and you get blotches.
#When to avoid it
For single-layer processes. Cyanotype, platinotype, palladium, Van Dyke, bromoil, gumoil, resinotype — every process you print in a single exposure. The marks serve no purpose; turn the option off so you don't clutter your negative.
For preliminary tests. If you're printing a test target to validate a calibration, you don't need registration marks — the target is its own reference system (the patches are aligned by construction).
For images with no defined border. If your image uses the whole paper surface with no margin, the registration marks are cut off at print time and lose their usefulness. Work with a minimal margin around the image to preserve the marks.
#Worth remembering
| Item | Value |
|---|---|
| Position | Four corners of the negative |
| Shape | Mini-diagram with several colored circles (Cyan, Magenta, Yellow) |
| Sub-modes | Color, Positive, Negative, CMYK |
| Consistency | Position and size identical across all layers of the same print |
| Precision reached | Half a millimeter at physical registration on a light table |
| Relevant processes | CMYK Aquaprint, color carbon, multi-pass gum |
| Not relevant for | Single-layer processes |
#The test
Generate two negatives in CMYK mode from the same image, with registration On and the Color sub-mode. Print both on separate transparencies. Stack them on a light table, without looking at the image — just the registration marks in the corners. You should be able to align the two marks of one corner perfectly in under a minute, gently sliding the second transparency. Check that the other corners align automatically too. If the marks overlap perfectly at all four corners, the alignment is validated.