Preparing a photo for print: the screen emits light and paper reflects it

A photograph can look perfect on the monitor and come out dark on paper. It is not a lab failure: the screen emits light, paper reflects it, and that difference changes decisions taken long before the file was sent. Understanding the path avoids most reprints.

The screen is always wrong in the same direction

The monitor has its own light; paper does not. When the display is too bright, the photo looks luminous even though the file is dark. The natural adjustment is to lower exposure until the image looks right there, and by then the damage is done: the file ended up darker than the scene.

That is why the first check is not of the file but of the workstation. Monitor brightness can be calibrated, but no single value works for every display and every room. What does help is keeping the editing light constant and not changing it with the hour or the mood.

The light you look at the print under counts too. A print in a dim room does not look like the same print under a dedicated lamp. If the paper will hang on a wall with warm, low light, that is the condition to anticipate, not the desk.

And there is a limit no profile solves. A soft proof anticipates colour, contrast and detail in shadows and highlights, but it does not show paper texture, reflections or the final lighting. For an important piece, a physical proof is still the only complete answer.

For anyone sending work to print, the consequence is concrete: the file that looks right on screen is not the one you get back on paper. Before sending it, lower monitor brightness to a stable level, check the magnified detail and look at a proof under the light of the place where the print will hang. Three habits, and they save the cost of reprinting.

PPI does not measure quality, it measures density

In labs you hear «300 DPI» all the time, and technically they are two different things. PPI counts how many pixels fit into each printed inch. DPI describes the printer's output. To know how far you can enlarge, PPI is the useful figure.

But the number alone says nothing. Changing resolution from 72 to 300 PPI without resampling adds not a single detail: it is the same file with another label. That is why a serious lab does not reject a file for reading 72. It looks at the pixel dimensions and the size you want to print. A 40 by 60 inch piece at 180 PPI can be excellent.

Resampling does add or remove pixels, and enlargement tools help, but more pixels do not equal more usable detail. Before printing, look at the enlarged result and hunt for artefacts.

The same happens with file format. A TIFF does not print better than a JPEG just for being a TIFF. What changes is what each one keeps: TIFF allows greater bit depth and saves without lossy compression, which is useful for master files and for delicate gradients such as a sky. JPEG compresses with loss, so it is best not to edit it and resave it many times. For a final order, a well-prepared JPEG usually beats a badly exported TIFF. And converting a JPEG to TIFF recovers nothing.

Defects that only show up large

There are defects you cannot see on a phone and that are the first thing to appear at 40 by 60 centimetres. Sensor dust, a crooked horizon, colour fringing at the edges, halos from too aggressive sharpening. If the image was built from several frames, check the transitions too: a blend with ghosting shows far more in large format.

Output sharpening is another step done at the end and for a specific material. It is applied after sizing, and matte papers usually need more than glossy ones. Excess shows as bright halos on edges, exaggerated texture or noise. It is worth asking whether the lab applies its own sharpening, so you do not double it.

Much of the result is decided by things that are not in the file. A textured paper can add atmosphere or compete with fine detail. Glossy metal gives deep blacks and also reflections that depend on the window next to it. A canvas with a gallery wrap takes part of the image around the sides, so leave margin when framing.

And the frame is not a formality. A textured frame can echo the trees in a woodland scene; a wider mat gives a busy composition room to breathe. Custom framing lets you respect the photograph's proportions instead of cropping it to fit a standard frame.

The test that puts everything in order is simple. Choose a photo that matters, print it and hold it in your hand. What appears there, what the screen hid and the paper revealed, teaches more than any previous adjustment. After that, preparing the next file is a different job.