Universal Contrast Sensitometric Metol Developer
Silberra U-2M is a single-solution universal contrast sensitometric developer for films and photo papers. The developer is a modification of ORWO-1 (108) developer. Silbera U-2M is an active developer that provides medium high and high image contrast and high maximal image density along with fine light sensitivity and wide gamma of halftones. Silberra U-2M can be used as standard and sensitometric developer for different photo materials: X-ray films, films for astrophotography and aerial photography, materials for microfilming, plates, photo papers, technical photo films, etc.
Metol, sodium sulfite anhydrous, hydroquinone, sodium carbonate anhydrous, potassium bromide, disodium edetate.
Preparing Working Solution
Working solution is prepared by pouring the contents of the packs into water while continuously stirring the solution (use glass stick or special plastic stirring stick for chemicals). Distilled or filtered water is strongly recommended.
The method of preparation is as follows:
1) Warm 700 - 800 ml of distilled water up to 37-42 Celcium degrees (use mix of hot and cold water, or use microwave to warm up the water).
2) Pour contents of pack #1 into the water while stirring until the powder is completely dissolved.
3) Pour contents of pack #2 into the water while stirring until the powder is completely dissolved.
Do not begin mixing the contents of pack two until pack one is completely dissolved. If any lumps of powder form in your solution, they can be broken down with your stirring stick. As soon as the working solution is ready (powders are totally dissolved), add cold water to make up to 1 litre and stir.
Allow the solution to cool to room temperature, nominally 20-22 C. Filtering the solution is not obligatory but recommended option. The working solution will be ready to use after 10-12 hours.
The Silberra U-2M Developer working solution can process photo films for 2-5 minutes (for films with low ISO) or for 5-10 minutes (for films with high ISO).
Development time for photo papers will be 1-2 minutes (to get maximum contrast), and for resin-coated photo paper time will be less than for fiber-based photo paper. The developer also works well with modern multi-grade paper. You may facilitate visual control over development of photo paper (while processing large sheets of paper) and also reduce contrast by diluting the working solution with distilled water to a ratio of 1:1. In this case the development time for photo papers will grow to 3-4 minutes.
Silberra U-2M working solution’s effective usage limit is 8 films of 135 type or 10 sheets of 18x24 cm photo paper per 1 litre. In fact, the usage limit can be doubled if you're not going to do sensitometric tests.
Usage of this developer requires constant agitation of liquid (rocking the cuvette with solution); each type of photo paper must be tested before use because this developer may cause veiling while working with general purpose photo papers.
Keep Silberra U-2M Developer in a cool, dry and dark place. Keep away from children. It is optimal to store your working solution in opaque, chemically inert and tightly sealed containers with minimal air space in order to reduce oxidation.
Expiry Date / Shelf Life
Sealed Silberra U-2M powder packs can be stored up to 12 months past the production date; U-2M Developer working solution can be stored in a closed bottle for 6 months past the production date, and, if used, no longer than for 4 weeks in a closed bottle.
Silberra developers and fixers must be disposed of in accordance with the rules and regulations of the country they are used in. Concentrated developers could be toxic and may harm the environment unless disposed in appropriate manner. Silberra recommends to use special disposal services provided by correspondingly licensed organizations which are eligible for photographic chemistry recycling/disposal.