Why Your Black and White Photos Printed Blue, Green or Purple
By John Albright, owner of Fromex True Black & White, Signal Hill, California
You spent real time on your black and white conversion. The grays looked perfect on screen. Then the prints arrived with a cool blue cast, a faint green in the shadows, or a purple tint in the midtones.
You are not imagining it, and in most cases your file is not the problem. Here is what is happening, how to check, and how to get prints that are truly neutral.
The short answer
Most black and white prints are not made on black and white paper. They are printed on color photo paper or with color inks. Neither one contains any true black and white material, so it has to build gray by mixing colors. When that mix is even slightly off, you see a tint.
How color paper makes gray
The standard photo paper used by most labs and online print services is color paper. It has three layers of dye: cyan, magenta and yellow. To produce a neutral gray, all three layers have to be balanced perfectly.
Small things tip that balance: a slight drift in the processing chemistry, a new batch of paper, or a printer that has not been calibrated that day. A color photo hides those shifts because it is full of color already. A black and white photo shows every one of them.
Why the tint changes when you move the print
Have you noticed that a print looks fine in the kitchen but green by the window? That is called metamerism. Colors built from dyes or inks can match under one kind of light and drift under another. Daylight, warm household bulbs and LED lights all have different color makeups, so a gray made from colored dyes can look different under each one.
Home printers can do it too
Many inkjet printers mix color inks into their grays to make smooth gradients. If the printer does not have a dedicated black and white mode with gray inks, or the settings and paper profile are not quite right, you can get the same blue, green or magenta cast at home.
First, check that your file is truly neutral
Before blaming the print, take one minute to rule out the file:
- Open the image in your editing app and use the color picker or info panel on a few gray areas: a shadow, a midtone and a highlight.
- In a truly neutral file, the red, green and blue values are equal (for example R 128, G 128, B 128).
- If they are not equal, your conversion has a tint built in. Split toning, a color grading preset or a film emulation filter are common causes.
- To remove it, convert the file to grayscale, or set saturation to zero, before you export.
If your file checks out as neutral and the prints still have a cast, the tint is coming from the print process, not from you. Our guide to preparing files covers export settings in more detail.
How to tell what your print is made on
| Test | What to look for |
|---|---|
| Turn it over | Color papers are often printed on the back with names like Fujicolor Crystal Archive or Kodak Endura. True black and white paper names a black and white paper maker, such as Ilford. |
| Move it between lights | A tint that changes between daylight and a lamp points to color dyes or inks. |
| Look at the deep shadows | Color paper often shows its cast most clearly in the darkest grays. |
| Ask the lab | Ask what paper black and white orders are printed on. A lab that prints on real black and white paper will tell you the brand. |
How to get truly neutral black and white prints
Option 1: Print on real black and white paper
This is the only way to take color out of the equation completely. A silver gelatin print is made of metallic silver in gelatin. Silver has no color to drift, so the print is neutral under any light, and a reprint next year will match this year.
That is the way we print true black and white. Your file is exposed by laser onto Ilford silver gelatin paper, then developed in black and white chemistry, like a darkroom print. See how we make black and white digital prints.
Option 2: Printing at home
Use your printer’s dedicated black and white or monochrome mode if it has one, choose the correct paper setting and profile, and make a small test print before committing to a big one.
Option 3: If your lab only has color paper
Ask for one test print before ordering a full set, and check it under the light where the print will hang. Be aware that a “black and white” checkbox at checkout often just converts your file to gray and still prints it on color paper.
Shooting film?
The same problem hits black and white negatives. Many labs print them on color paper too. We print film on real black and white paper. Get B&W prints from your negatives.
Want black and white prints with no color cast? We print on real Ilford silver gelatin paper, check every print by eye, and ship worldwide. Order black and white digital prints
