Flat negative

Owned by Reading the Negative as Evidence, whose table of four cases puts this one at low contrast with the overall level free to be anything, on the rule that density is mostly exposure while contrast is mostly development. That page adds the case this entry should not be confused with, the negative that is thin and contrasty, which is two knobs turned in opposite directions and is what a pushed film is. This entry came earlier from Break/Fix — the developer that went wrong, one of three that session owed the atlas, and has been checked against the owner.

What you see

The steps run together — fewer separable steps between the first density and the maximum. On a pictorial negative, a scale that is compressed, most often at the bottom, so the shadows are grey and lifeless.

Flatness and thinness usually travel together, and the pair is the signature of under-development. Flatness without thinness is a different animal and points at non-image light.

Likely causes

1. Under-development. Kodak’s own summary is one line — underdevelopment gives a decrease in density and contrast in the control strip and a loss of density, contrast and shadow detail in the negative.
2. Non-image light, which lifts the bottom of the scale without moving the top - flare, a leak, safelight fog or an exhausted developer.
3. A subject with less range in it than the reading assumed, which is not a fault at all.

What is happening: the chemistry and physics

Contrast is the rate at which density rises with log exposure, and development is what builds it. Stop development early and the highlights, which are developing fastest, lose the most

• so the top of the scale comes down towards the bottom and the range compresses.

Non-image light does the opposite thing to the same measurement. A constant addition of exposure is negligible where the picture already delivered a lot of light and dominant where it delivered almost none, so the shadows lift while the highlights barely move. The toe compresses and the contrast falls, and the negative is flat without being thin.

That is why the two causes must be separated by looking at which end moved, not at the contrast figure.

!Four things flatten a negative, and two questions separate them

Cause	Crosses the strip under the paper stop?	On the unexposed control sheet?
Flare	No — it came through the hole, so it stops at the image circle	No
A leak	Yes	No
Safelight fog	Yes, uniform right to the cut edge	Yes
Exhausted or oxidised developer	Yes	Yes

The last two are separated in turn by the maximum black — a bad developer gives a low maximum black as well as lifted shadows, and a fresh-developer reference sheet settles it.

Diagnostic questions

• Is it thin as well as flat? Both together points at development. Correct overall density with dead shadows points at non-image light.
• Is the clearest step as dark as the control’s? If yes, the developer is doing its job.
• Does the veil cross the paper-stop strips, and is it on the control sheet? The table above turns the answers into a name.
• What is the maximum black like? A maximum black that is not black points at the bath rather than at the light.
• Was the subject actually contrasty? A flat subject photographed correctly gives a flat negative, and that is a printing decision rather than a fault.

Corrective action

Nothing on the negative, but a flat negative prints. Raising the paper grade restores contrast, at the cost of whatever separation was never recorded in the shadows.

Where development was the cause, extend it on the next film — and where non-image light was the cause, extending development makes it worse, because it develops the fog along with the picture.

Prevention

Carry an unexposed control sheet through every session. It exonerates or convicts the box, the safelight and the developer in one operation and costs one sheet.

Run a process-control strip before a session that matters.

Watch for the contrast symptom of safelight fog specifically. ILFORD warn that low-level fogging may show not as visible fog but as a general loss of contrast, so a flat negative with a clean-looking sheet is worth a safelight test.