442 



HANDBOOK OF PHOTOGRAPHY 



An idea of the color changes that may be effected may be obtained from Table VI 

 below, taken from Ilford's Manual. It is applied to Ilford Chlorona paper which is a 

 typical chlorobromide. 



Developer P'ormtjla for Ilford Chlorona Paper 



Glycine 60 gr. 3.4 g. 



Hydroquiiione 60 gr. 3.4 g. 



Sodium sulphite 2 J-2 oz. 62 . 5 g. 



Sodium carbonate 4 oz. 100 



Potassium bromide 6 gr. . 35 g. 



Water, up to 20 oz. 500 cc. 



Table VI. — Color Control Table for Above Developer 



Exposure 



Warm — black | Normal 



Sepia 2 times 



Warm sepia 3 



Red brown 4 



Red 5 



Developer Potassium bromide, 



dilution 1 10 per cent, per oz. 



Full strength 



5 times 

 10 

 15 

 20 



None 



20 minims 



60 

 100 

 120 



1 cc. 

 3 

 5 

 6 



Developer time, 

 min. 



m 



5 

 10 

 15 

 20 



To secure "warm" tones, i.e., black mixed with brown, the amount of bromide is 

 increased and the exposure is increased. If the exposure is n'ot increased, the final 

 print color will be the same as if the print had been developed in the solution with less 

 bromide, but it will take longer for the final color to be attained. 



Slow papers will respond more readily to changes of potassium bromide than the 

 faster papers. Changes of tone should be effected by varying the amount of bromide 

 plus the variations in exposure time, rather than in merely varying the time in the 

 normal developer solution for various exposures. Increased exposure and under- 

 development in a normal developer will produce warm tones, but the shadow detail will 

 be poor, the shadows will not be black, and the print will not be uniformly colored. 



Modifications in Development. — Although the formulas recommended by the manu- 

 facturers are to be followed wherever possible, the following effects of changing 

 formulas are to be noted in case unusual conditions are met. 



Increasing metol and decreasing hydroquinone makes softer prints. Reversing 

 these changes produces greater contrast and brilliance. 



Additional carbonate in the developer increases developing action and yields 

 black tones without an olive cast. Less carbonate gives softer results and slows up 

 developing. 



To inci'ease contrast, increase h.ydroquinone and carbonate. For less contrast, 

 double usual amount of metol, halve the hydroquinone, and halve the carbonate. 



Increase bromide to slow development, to decrease fog, to clear high lights, to add 

 warmth of tone. 



Typical Print Developers. — The chapters on Development contain numerous 

 developing formulas for papers. The formulas on page 443, however, are those sug- 

 gested by manufacturers whose papers are widely used in this country. 



Inspection during Development. — Under a red- or yellow-printing safe light, it is 

 often difficult to judge print color correctly. Prints appear darker under the safe light 

 than in white light. It is wise, therefore, to fix a test print and to inspect it by white 

 light to determine if it is satisfactory. Another expedient is to use a green safe light 

 (Wratten Series OA). Under this light the prints will appear more like they will under 

 white light. (For safe light for certain papers, see chapter on Darkrooms and Dark- 

 room Practice.) 



