This section is from the book "Complete Self-Instructing Library Of Practical Photography", by J. B. Schriever. Also available from Amazon: Complete Self-Instructing Library Of Practical Photography.
Prints Stained Or Scratched. If the print on the temporary support has been cleared in an alum bath in which the alum has not been entirely dissolved, the film of the print will become stained and scratched by the undissolved part of the alum coming in contact with it. The alum bath, in which powder potash alum should be used, should be filtered before use, and must be used cold.
Dark Specks On The Print Sometimes Surrounded By Round White Spots. If the wash waters or any of the developing baths are made up of water containing iron, or small iron particles, small dark specks will be left on the face of the print. These can be picked out when the print is dry, and the print re-spotted. If the water you use from the tap is not clear or free from iron, filter as it comes from the tap.
Blisters On The Image. These are caused by the air in the final support, which has not been properly soaked previous to squeegeeing to the tissue. There will be blisters wherever the air bubbles appear and are not removed. The final support should be allowed to remain in the water until it becomes semi-transparent or thoroughly saturated. Minute bubbles will appear on the prepared surface in about three minutes, all of which should be carefully removed.
330. Perfect contact between the support and the tissue can only be attained by thorough soaking of the support in water and heavy pressure of the squeegee when bringing the support and tissue together.
When Using Plain Glass For First Support, In Order To Obtain A Brilliant Surface, Portions Of The Print Appear Dull. If the glass used for the first, or temporary, support has not been thoroughly cleaned, it will be difficult to get an even coating of wax on it. The surface of the plate must be carefully polished, and the waxing solution rubbed over it very quickly and evenly, avoiding going over the same spot twice, as this would give uneven waxing and produce dull spots on the print. Any moisture coming in contact with the waxing flannel, or with the wax on the plate, will ruin the brilliant surface of the print.
When Preparing Collodion, It Becomes Milky. The collodion emulsion should be prepared in a bottle which is thoroughly dry. A good plan to dry out a bottle which has been washed is to pour in a little alcohol, rinse it around, and then pour out the alcohol, leaving the bottle to drain.
Unable To Coat The Glass Evenly. Some little difficulty may be experienced in getting an even coating of collodion at first on the plate. The plate should be held on the tips of the thumb and first and second fingers, pouring the collodion on the corner farther from you, gradually tipping the plate so the collodion will spread evenly all over. The excess collodion should be drained back into the bottle. By rocking the plate slightly a perfectly even coating can be obtained, which will soon set.
Unable To Obtain A Matt Surface Effect When Using Plain Glass For A Support. To obtain a matt effect with a plain glass the plate must first be waxed and polished, and then given a coating of plain collodion. The plate with the collodion coating must be placed in clean water for fifteen or twenty minutes, to remove all the ether or alcohol from the film. If either of these liquids remain they will cause spots and stains on the print.
Film Becomes Injured When Transferring The Print From Glass. The film, or print, is at all times exceedingly delicate, and unless very great precautions are taken in all the transferring manipulations it is liable to become injured and torn. Also, the pressure of the squeegee when bringing the print into contact with the final support should be evenly applied.