64 DO’S AND DON’TS OF TINTING 4.8 ALL RIGHTS RESERVED © LAB MOD SYSTEM FRAME PARTS LAB CONSUMABLES TOOLS PLIERS EQUIPMENTS LENSES REFRACTION & ORTHOPTIC INDEX CLEANLINESS The biggest problem in tinting is contamination. The pot must be absolutely clean before fresh tints are mixed. Any residual colour remaining in the pot will affect the new colour. Boil neutralizer in the pot to ensure perfect cleanliness. Thoroughly rinse with clean water. PREPARING THE TINT Half fill the pot with distilled water and heat to 60°C (140°F) then add dye powder. Stir mixture until dye is completely dissolved. For liquid dyes shake the bottle well before adding hot water. Add some distilled water and flush tint pot to ensure all the contents are being used. If required add more water to make up 1 litre of dye solution. USE DISTILLEDWATER Limestone, chlorine and water impurities can often cause inconsistencies in dye properties. Impurities can cause colour “haloes”when tinting lenses. FLUSH THE BOTTLES WELL Make sure the tint pot is completely emptied of dye and dye sediment when mixing as it affects the composition of the colour. DO NOT MIX DYE WITH COLDWATER Often dyes will not dissolve easily in cold water and deposits may form in the bottom of the pot. Conversely, if the dye concentrate is left to settle, the high hot plate temperature may cause crystallisation which will also affect colour consistency. Stir dyes regularly during preparation. DO NOT MIX THE DYE WITHWATER OVER 90°C (194°F) The dye may crystallise and will not mix evenly. This could affect colour consistency. ADVANTAGES OF MIXING THE COLOUR AT 60°C (140°F) The colour mixes homogenously as it gradually reaches the temperature of 92°C-95°C (198 - 203°F).Mixing and stirring the dyes at 60ºC for 10-15 minutes makes it very stable and ensures a homogenous colour mix. HEATING ANDWATER LOSS REPLACEMENT Slowly heat the solution for about 20 minutes until it reaches 92°C-95°C (198 - 203°F). Do not heat with a flame as that tends to concentrate the heat whereas it should be evenly spread around the dye pot.During tinting water is lost through evaporation. It is recommended that small quantities of distilled water be added to the bath to compensate for this loss. It should be at the same pot temperature when added. DO NOT HEAT QUICKLY The temperature on the bottom and around the sides of the container is usually higher than in the centre. Fast heating may cause crystallisation which effects a colour consistency and dye life. WATER REPLENISHEMENT Add small quantities of distilled water regularly to overcome loss due to evaporation.Wait until the dye temperature has recovered to 92°C -95°C (198°F -203°F). As more water is added, colour strength will change. A top-up of dye may also be necessary from time to time. MIXING AND CORRECTING COLOURS When mixing and correcting colours ALWAYS rinse the lenses and lens holder in clean water before proceeding to the next colour. Contamination is the quickest and the most common way of spoiling colour consistency. This rule also applies when adding other properties like hard coatings and when neutralising or bleaching out colour. The rule is - thoroughly wash the lens and lens holder in clean water before transferring them to another colour or process.
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