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.
Practice Work. The chief success of platinum printing lies in correct exposure. Of course, all negatives will not make good platinum prints, but prints from some negatives, which would ordinarily appear flat and dull if developed in the ordinary way, may be improved by manipulating in the developer. While the different grades of platinum paper work exactly alike, yet some produce more brilliant prints than others. Coarse papers are better suited to large negatives, while smooth papers are to be preferred for small negatives, so be guided accordingly. It is advisable for your first work to make a liberal number of prints using a medium rough paper, developed in normal bath prepared according to formula. After you have become somewhat familiar with the work, the three baths mentioned in the previous instruction should be prepared and each print developed in the bath suitable to the quality of the print to be developed. By a little dodging in the different developers, much improvement can be made over normal developing.
570. Your test prints should all be filed in your proof file with notes written on the back giving full information regarding the manipulation for the producing of the results. Should you meet with failures at first, by referring to the difficulty department you will undoubtedly find the cause, remedy and prevention thereof.