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.
Metol Poisoning. Metol is of a poisonous nature attacking some people more than others. It often causes an itching and soreness of the skin. With ortol there is little likelihood of danger and practically the same results can be produced as with metol. If one is subject to metol poisoning, the following ointment will be found to give almost immediate relief:
Ointment Preventing Metol Poisoning.
706. Add to this a drop or two of oil of lavender, which destroys all unpleasant odors. Rub well into the skin. It is also excellent for cuts or burns.
707. Another positive cure for metol poisoning, but one which is rather severe, is soaking the hands twice a day for 15 minutes in a strong solution of salt and vinegar.
Developing Notes. There are a number of suggestions as to developing, which should be very thoroughly studied and carefully followed to insure good results. Prints may be developed by immersion in the solution or the developer may be applied with a tuft of cotton or a brush. If the former method is to be employed the developer should be placed in a tray somewhat larger than the size of the paper you are using. To the right of this place a tray of water and next to that the tray for the fixing bath.
709. The prints should be immersed, face up, in the developer and then evenly covered with the solution at once, to insure uniformity of development. This method of development is the most satisfactory for the beginner; but for the advanced worker, the cotton or brush method may be employed instead of the developing tray. Provide yourself with a sheet of glass somewhat larger than the print to be developed. Pour the developing solution into a cup, tumbler or graduate. After the paper has been exposed, place it face up on the glass, then thoroughly saturate the cotton or brush with the developing solution, and pass it quickly over the surface of the print, applying the developer evenly and abundantly. If the exposure is correct the image will appear gradually and complete development will be effected in about 30 seconds, if the "Special " Velox has been used. The " Regular " Velox will require about one-half as much time. If the print flashes up very quickly and at once grows black, it is a sign of over-exposure in printing. If under-exposed, the print will, on the contrary, develop very slowly and it will finally be found weak in the important parts.
710. If the immersing method is employed and air-bells gather on the surface of the paper, be sure to break them with the tips of your fingers, or with a tuft of cotton. If not broken they will leave white, undeveloped spots on the print. If you find that the highlights (whitest parts of picture) are gray, it will be necessary to add to the bath a few more drops of a 10% solution of bromide of potassium. Be careful, however, not to use more bromide than is absolutely necessary to secure pure whites, as an excess of bromide will not only restrain the developing and produce contrasty prints, but will also produce greenish prints. Watch the process of development carefully and when you find the print is almost dark enough remove it from the developer. It is necessary to act quickly as each fraction of a second causes the print to grow darker. If the exposure has been too short, you can not expect to make the print dark enough by prolonged development.
711. If under-printed, prolonged development will produce a stained print, generally a yellow cast over the entire print. Remember that hydroquinone in the developer produces contrast while the metol produces detail even to flatness; so if in printing you have given the correct exposure and your results are flat add a trifle more hydroquinone to the developer. This can be done by adding a few grains to the solution, being careful that they are thoroughly dissolved before developing more prints. If, on the other hand, the results are too contrasty add a trifle more metol. For the beginner we would advise making no attempt to change the proportions of the developer. Later on, however, when more experience has been acquired it will be well to experiment along these lines. It is advisable when the bulk of the solution is reduced to replenish with fresh developer added to the old, or used bath.