D-76 development times: stock vs 1:1 for Tri-X, T-Max and Plus-X
Kodak's D-76 technical data sheet (publication J-78, revised December 2017, Kodak Alaris) gives times for stock and for 1:1. In a small tank at 20 °C (68 °F), Tri-X Pan takes 8:00 in stock D-76 and 10:00 at 1:1. The tables below copy the sheet's roll-film rows. Kodak calls the times a starting point and suggests changing them by 10 to 15 percent if your negatives come out too flat or too contrasty.
Stock and 1:1 at 20 °C
| Kodak roll film | Stock | 1:1 | 1:1 adds |
|---|---|---|---|
| T-Max 100 Professional | 9:00 | 12:00 | +33% |
| T-Max 400 Professional | 8:00 | 12:30 | +56% |
| Verichrome Pan | 7:00 | 9:00 | +29% |
| Plus-X Pan / Plus-X Pan Professional | 5:30 | 7:00 | +27% |
| Tri-X Pan | 8:00 | 10:00 | +25% |
| Tri-X Pan Professional | 8:00 | n/a | n/a |
| High Speed Infrared | 8:30 | n/a | n/a |
Small tank, agitation at 30-second intervals. n/a means the sheet prints no 1:1 time for that film. The "1:1 adds" column is my arithmetic on Kodak's two times. Kodak notes that tank times under 5 minutes may develop unevenly.
1:1 across Kodak's temperature range
Kodak prints stock and 1:1 times at 18, 20, 21, 22 and 24 °C (65, 68, 70, 72 and 75 °F). These are the 1:1 rows for a small tank, so you can read your own temperature straight from the sheet.
| Kodak roll film | 18 °C | 20 °C | 21 °C | 22 °C | 24 °C |
|---|---|---|---|---|---|
| T-Max 100 Professional | 14:30 | 12:00 | 11:00 | 10:00 | 8:30 |
| T-Max 400 Professional | 14:30 | 12:30 | 11:00 | 10:00 | 9:00 |
| Verichrome Pan | 11:00 | 9:00 | 8:00 | 7:00 | 6:00 |
| Plus-X Pan / Plus-X Pan Professional | 8:00 | 7:00 | 6:30 | 6:00 | 5:00 |
| Tri-X Pan | 11:00 | 10:00 | 9:30 | 9:00 | 8:00 |
The sheet also gives large-tank times (agitation once a minute), sheet-film times for trays and large tanks, T-Max P3200 at EI 400 to 6400, push times and rotary-tube times for stock. I left those out to keep the page short.
Other temperatures
Kodak's range is 18 to 24 °C. For a temperature in between, put the 20 °C time into the temperature calculator. It uses a curve fitted to Ilford's chart, so its answer can differ a little from Kodak's own column.
Worked example: Tri-X at 1:1 in a 500 mL tank
1:1 means one part stock to one part water. For 500 mL of working solution that is 250 mL of stock and 250 mL of water, which the dilution calculator opens with. Kodak says to dilute just before use and to discard the solution after the batch.
Kodak's time for Tri-X Pan at 1:1 and 20 °C is 10:00. At 22 °C the sheet prints 9:00, and the temperature calculator gives 8:12 for the same step. At 24 °C the sheet prints 8:00 and the calculator 6:51. When the sheet has your temperature, use the sheet. The calculator at 23 °C covers a temperature it leaves out.
Agitation
The small-tank times assume this routine. Fill the tank with developer, start the timer, lower in the reel and tap the tank on the bench from about 2.5 cm (1 inch) to dislodge air bubbles. Agitate up to 5 cycles at the start (5 to 7 cycles in 5 seconds for T-Max films), then let the tank sit for the rest of the first 30 seconds. After that, agitate for 5 seconds at 30-second intervals, 2 to 5 cycles each time depending on the contrast you want and your tank.
For an invertible tank one cycle is turning the tank upside down and back. Times for large tanks assume agitation once a minute. Kodak asks for irregular movements, so the developer does not flow over the film in one direction.
Capacity, keeping time and replenishment
Stock D-76 keeps 6 months in a full, tightly closed bottle and 2 months in a half-filled one. In a tank with a floating lid the working solution keeps 1 month, and in a tray 24 hours.
Without replenisher, a gallon (3.8 liters) of stock develops 16 rolls (135-36 or 120), or 4 per liter. Kodak asks for 15 percent more time after every four rolls per gallon. At 1:1 the capacity is 8 rolls per gallon (2 per liter), with time compensation. Kodak says to use the diluted solution for one batch, discard it, and not reuse or replenish it. If you develop one 135-36 roll in a 237 mL (8-ounce) tank or two in a 473 mL (16-ounce) tank at 1:1, add 10 percent to the time.
With Replenisher D-76R, add 22.2 to 29.6 mL (3/4 to 1 fluid ounce) per 135-36 or 120 roll to stock D-76 and keep the time unchanged. A gallon then handles 120 rolls of 135-36. Kodak says to discard the developer after 9600 square inches of film per gallon. For T-Max films it describes a modified replenisher (5 parts D-76 to 1 part D-76R, 70 mL per roll).
Source
All times and figures come from KODAK Developer D-76, publication J-78, revised December 2017, Kodak Alaris, which I opened and read for this page. Its full-strength table prints "7v" for Tri-X Pan at 21 °C where a time should be. It looks like a misprint, and this page doesn't use that cell. Check the sheet when a result matters.