Skip to main content

What went wrong?

My negatives have a metallic or coloured sheen

Negatives and slides

What you're seeing

A thin, metallic-looking layer on the emulsion that can look reddish or greenish depending on whether you look at it by reflected or transmitted light.

Check this first

Check this first

Look at the strip by reflected light, then on a light box. Does the colour change between the two?

Likely causes, most common first

  1. 01

    Calcium scum or drying marks on the surface

    Common
    How to tell
    A dull or chalky deposit, often on the shiny base side, that does not change colour with the angle of light. Common with hard water.
    Test it
    Rewash the strip, use wetting agent, and wipe gently with a damp chamois: marks that go were a surface deposit.
    The fix
    Use wetting agent in the final rinse and an acid stop bath, which also removes calcium scum from the developer.

    Sources Eastman Kodak Company, Processing Chemicals and Formulas for Black-and-White Photography (Kodak Publication J-1), 7th edition; Ilford Photo (Harman Technology), Common Processing Problems; Eastman Kodak Company, Processing KODAK Motion Picture Films, Module 15: Processing Black-and-White Films

  2. 02

    Dichroic fog from developer carried into the fixer

    Rare
    How to tell
    A metallic or coloured sheen that changes colour with the angle of light. More likely if you skip the stop bath or water rinse, or use tired fixer.
    Test it
    Process a scrap roll with an acid stop bath and fresh fixer. If the sheen does not appear, carry-over was the cause.
    The fix
    Use an acid stop bath, or a thorough water rinse, between developer and fixer, and fix in fresh fixer. No manufacturer gives a reliable home fix for film already affected.

    Sources MACO Photo Products (Hans O. Mahn GmbH & Co. KG), B&W Stop Bath Acetic Acid 60% data sheet (Art. No. APS10); Eastman Kodak Company, Processing Chemicals and Formulas for Black-and-White Photography (Kodak Publication J-1), 7th edition; Wikipedia, Fogging (photography)

Avoiding it next time

  • Use a stop bath or thorough rinse before the fixer.
  • Keep fixer fresh.

Go deeper