Quick Answer

Mix Kodak Xtol at 68–75°F (20–24°C) using distilled water and dissolve the powder completely. Store the stock solution in airtight, full containers away from light and heat. Properly stored, Xtol lasts about 6 months in full, sealed bottles.

Why Mixing and Storage Matter for Xtol

Kodak Xtol is a fine-grain, high-acutance black and white developer known for its excellent shadow detail and long tonal range. But its performance depends heavily on how you mix and store it. Unlike some liquid concentrates, Xtol comes as a powder that must be fully dissolved into a stock solution. Improper mixing can leave undissolved particles that cause uneven development, and poor storage can shorten its shelf life dramatically.

Because Xtol is sensitive to oxidation, the key to longevity is minimizing air contact. Many home film processors find that storing the stock solution in multiple smaller glass or PET bottles, filled to the brim, gives the best results. The developer can also be stored as a working solution for a few days, but the stock solution is more stable.

Choosing the Right Water and Container

Use distilled or deionized water for mixing. Tap water often contains chlorine, minerals, or other impurities that can react with the developer chemicals and reduce activity. Distilled water ensures consistent results and helps the powder dissolve more completely.

For storage, avoid metal containers. Glass or high-density polyethylene (HDPE) bottles work well. The container must be able to seal airtight. A common mistake is using a bottle that is too large, leaving a lot of air above the liquid. Instead, use several smaller bottles so each one is nearly full. This drastically slows oxidation and extends shelf life.

How to Tell If Your Xtol Has Gone Bad

A fresh batch of Xtol stock solution is a clear, pale yellow liquid. If it turns dark brown, develops a strong sulfur smell, or forms a precipitate, it has oxidized and should be discarded. Using expired or spoiled developer can lead to weak, uneven, or completely blank negatives.

Some photographers use a simple test: mix a small amount of working solution and drop in a piece of exposed film leader. If the leader turns dark within a few minutes, the developer is still active. If there is little or no change, the developer is exhausted. This test is a quick check, but for critical work, stick to fresh stock.

Step-by-Step Mixing and Storage Guide

  1. Prepare Your Water and Equipment: Start with distilled water at 68–75°F (20–24°C). Use a clean plastic or glass container that holds at least 5 liters. Avoid metal utensils or containers as they can contaminate the developer. Checkpoint: Water temperature outside this range can cause incomplete dissolving or degrade the chemicals.
  2. Dissolve the Powder Completely: Slowly add the powder to the water while stirring gently but continuously. Do not pour water into the powder. Stir until no visible particles remain. This may take several minutes. Let the solution sit for a few minutes, then stir again to ensure full dissolution. Common mistake: Undissolved particles can cause uneven development. If you see sediment, continue stirring or gently warm the water (still within 68–75°F).
  3. Fill Storage Bottles to the Brim: Pour the stock solution into clean, airtight glass or HDPE bottles. Fill each bottle completely so there is no air space. Seal tightly. Label each bottle with the date mixed. Checkpoint: Air in the bottle accelerates oxidation. Use multiple small bottles rather than one large one to minimize air exposure after opening.
  4. Store in a Cool, Dark Place: Keep the sealed bottles in a dark cabinet or closet at room temperature (60–75°F). Avoid temperature extremes and direct light. Do not refrigerate unless you plan to use it within a few days, as condensation can form and dilute the developer. Verdict: Properly stored, Xtol stock solution remains reliable for about 6 months. After that, test it before use.
  5. Use and Discard Working Solution Promptly: When mixing working solution from stock, use it the same day if possible. Xtol working solution oxidizes quickly and should not be stored for more than 24 hours. Discard used developer after processing—do not reuse it. Next step: For one-shot development, mix only what you need for that session to avoid waste.

Product Used in This Guide

  • Kodak Xtol Professional Film Developer - Makes 5 Liters: Kodak Xtol Professional Film Developer makes 5 liters of stock solution when mixed according to instructions. Please note that this product is only available for Store Pickup only as we are not able to ship photographic chemicals. This 5-liter batch size is ideal for home darkrooms. The store pickup limitation means you need to plan ahead and pick it up locally, but the price per liter is very economical for regular film processing.