Frame and background

When you generate a digital negative, the file's final composition isn't just the image. Around your useful image there's an area — the paper margin — that will also be exposed through the transparency. If you don't control what happens in this area, you can end up with paper margins exposed by accident, or a blurry boundary between the image and the margin.

The Frame and Background options give you that control. The Background sets what happens in the area around your image — either it blocks UV light (black background), or it lets it through (white background). The Frame adds a visible line that marks exactly the outline of your useful image on the final print.

#How it works

The Background — black or white. On a standard negative (Negative mode), black background is the default. The black area on the transparency blocks UV light, so the paper around the image stays white (intact, unexposed). That's what you want to preserve presentation margins.

Conversely, a white background lets light through. The paper around your image will therefore be fully exposed — which produces a blue area (cyanotype), black (carbon), or colored (Aquaprint), depending on the process. Useful for "edge-to-edge" prints where you want the whole paper surface treated.

The Frame — none, thin, or thick. Adds a closed rectangular line between your image and the background. The line is drawn on the negative and physically reproduced on the final print.

• None: no frame, direct transition between the image and the background.
• Thin: a few-pixel line — gives a discreet outline that marks the boundary without dominating visually.
• Thick: a wider line — produces a strong graphic effect, like a mat board built into the print.

The frame color is automatic. Calibration Flow chooses the color opposite to the background so the frame is always visible:

• Black background → white frame (which appears colored on the print: blue on a cyanotype, etc.).
• White background → black frame (which produces a light line on the print: bare, unexposed paper).

You don't have to choose the frame color — it's dictated by your background choice.

#Why it matters

To structure the final print visually. A well-printed alt-process image gains from a defined outline. Without a frame, the edge of the image can look blurry or irregular (depending on clearing). A clean thin frame gives a professional finish that turns the print from "test" into "work".

To protect presentation margins. A black background with a centered image leaves a border of blank paper all around — useful for mounting under a mat board or for traditional framing. Without a black background, those margins would be exposed like the rest.

For consistency across a series. If you produce five prints of the same series, using the same frame and the same background gives instant visual consistency. The technical detail becomes an aesthetic choice for the series.

#When to avoid it

For prints where the image uses the whole paper. If you're making an edge-to-edge print where the image goes from one corner of the paper to the other, you turn off the frame and use a white background. The negative then prints an image that covers the whole transparency.

For prints meant to be cropped later. If you plan to cut your prints on a guillotine to custom dimensions, the negative's frame will be lost in the crop. No point adding it.

For calibration tests. On a calibration target, you don't need a frame — the frame would clutter the useful measurement area without adding value. Keep "no frame" for all your test negatives.

#Worth remembering

#The test

Generate two versions of the same negative with two combinations: (1) black background + thin frame, (2) white background + no frame. Print both on transparency and expose on cyanotype paper. On the first print, you should see the blue image in the center with a white paper margin around it and a thin blue line marking the boundary of the image. On the second, the whole paper should be blue-exposed, with no white margin. If you see something else, check the export panel options before generating.