Test sheet: the exposure ladder

What's on the sheet

Five bands, one per exposure time. You give the ladder a single number — the total — and it divides it into five even steps. Ask for 10 minutes and the bands are 2, 4, 6, 8 and 10; ask for 20 and they're 4, 8, 12, 16 and 20.

Each band's header names the time it comes off, written the way you'd read it on a clock (10m, not 600), because the sheet has to be legible on a table in the sun with the clock running.

Inside every band, two tones sit side by side: the tone you currently have selected, paired against black. Each is the same step wedge — full tone at the top, clear film at the bottom. If your selection is black, the ladder pairs against yellow instead, since black against black is two identical columns.

Why the two tones are neighbours, not opposite edges

Hand-coating varies across a sheet. Compare two tones at opposite edges of the paper and you're measuring the coating as much as the tone. Sitting them side by side inside each band — repeated at five exposures — removes that.

The bands are separated by wide clear gutters so you can lay a card down a boundary and cover the rest while you expose.

How to run it

• Print the sheet onto film and contact print it as usual.
• Cover the whole sheet, then uncover one band at a time as the clock passes each mark — so every band receives its own cumulative time. The gutters are where the card goes.
• Process, dry, and read.

The clear strip along the bottom is for your own marker line — a true-opaque control, which is what made the first version of this test legible at all.

Reading it

You're looking for the shortest exposure at which the darkest patch reaches full black and the light end still shows separated steps. Longer than that buys nothing and starts filling in the highlights.

Compare the two tones within a band, not across bands. If one tone reaches full depth a band earlier than the other, that's a genuine difference in how much UV it blocks — and it's also the answer to whether your chosen tone costs or saves you time.

This is a different question from the colour sheets, which is why it has its own menu item and no Basic/Advanced choice. Those ask which tone; this one asks how long.

How to read any of these sheets

All four work the same way, and none of them can be judged on screen:

• Print the sheet onto transparency film, exactly as you print a negative — same printer, same film, same settings.
• Contact print it onto your sensitized paper, with your own light source and your own exposure.
• Process it as usual, dry it, and read the answer off the paper.

The blank bottom row is clear film. No ink at all. It exposes fully and prints your darkest tone, so it's the reference every column above it is read against.

Column headings are printed in clear, on a darkened band. Clear is the only "ink" guaranteed to print dark, so the labels stay readable on the finished print rather than disappearing.

Judge it dry, not wet.