X-TOL Developer

About this developer

XTOL is a favorite film developer among many photographers, marketed by Kodak since 1996. It uses a somewhat unusual combination of methylphenidone (phenidone) and ascorbic acid as its developing agents—without hydroquinone. The developer effectively brings out the film’s light sensitivity, renders detail in the shadows, produces fine grain, and has excellent stability. The challenge of reproducing it at home lies in two “problematic” ingredients in the proprietary formula: sodium metaborate (Codalk) and sodium isoascorbate, which are not interchangeable with the more readily available borax and ordinary ascorbic acid, even though their names sound similar. According to the formula’s manufacturer, a freshly prepared developer filled to the brim can be stored for up to 6 months, and 1 liter of developer can process up to 12–15 rolls of film. For normal development, the processing time should be slightly increased (by 10–20%) compared to standard developers such as D-76.

Character

A modern ascorbate-phenidone developer. It maintains sensitivity well, produces fine grain, offers high detail, and has a wide tonal range. One of the best all-purpose developers for scanning.

Best films

Kodak T-Max 100/400, Tri-X, Ilford Delta 100/400/3200, HP5+, FP4+, Kentmere 100/400, Fomapan 100/200/400. Moderate push.

How to Prepare and Use

1. 1Take about 750 mL of hot (≈50–55°C) water and dissolve the contents of Bag A in it one by one: anhydrous sodium sulfite (10 g), Trilon B (1 g), Codal (4 g), and methylphenidone/phenidone (0.2 g).
2. 2After packet A has completely dissolved, add the contents of packet B in small portions: sodium sulfite (75 g), sodium metabisulfite (3.5 g), and sodium isoascorbate (12 g), ensuring that all substances are completely dissolved.
3. 3Add distilled water to bring the total volume of the solution to 1 liter, and filter if necessary. After adding Packet A, the solution may be yellow or light brown—it should become colorless once all the substances have completely dissolved.
4. 4Prepare the working developer by mixing stock solutions A and B in a 1:1 ratio; It is permissible to further dilute the working solution with water in a ratio of 1:1, 1:2, or even 1:3, although the manufacturer of the formula does not guarantee normal results in the latter two cases.
5. 5Develop for 10–20% longer than with standard developers such as D-76.
6. 6If Codal is unavailable, you can use 2.1 g of sodium metaborate tetrahydrate or 1.59 g of potassium metaborate (1¼-hydrate) instead of 1 g of Codal—their properties are identical, but an accurate conversion based on molar mass is required; methylphenidone can be replaced with an equal amount of phenidone.

Development times for different films

Time — Kodak’s official starting values for its proprietary XTOL (stock solution, small tank, 20°C, Publication J-109, Table 1). This homemade recipe replicates the formula, but given differences in reagent purity, the author recommends increasing the processing time by 10–20% compared to developers such as D-76 during the first test run.