| Oxalate | 6 oz. |
| Iron | 2 oz. |
| Bromide | 2 drs. |
Always pour the iron into the oxalate solution, then add the bromide, and having placed the exposed plate in the dish pour the developer upon it, covering the surface of the plate as quickly as possible and removing any air bells that may stick to the surface.
Keep the solution in motion on the surface of the plate and in a short time the image will begin to appear, the high lights first, then the intermediate shades, last of all detail will be seen in the shadows. Now pour the developer off, take the plate out of the tray and look at the back of it. If the subject or image can be distinctly seen it may be considered finished and only needs to be washed and fixed.
If the plate has been over-exposed, which will be indicated by the image appearing quickly, wash off the developer with water, add more bromide to the solution and immerse the plate again.
If, on the contrary, the plate has not had enough time, it will be indicated by developing very slowly and with a very thin and weak image; when such is the case add more of the iron solution, however, not more than to make the proportion of the iron nearly p60 one-fourth of the whole solution. More than this proportion will cause a yellow precipitate, which will settle on the surface of the film and destroy it. If by this course you succeed in securing sufficient detail in the shadows, the negative may afterwards be strengthened.
It is as well, however, when a plate is found to be undertimed (and it is possible to make another from the same subject) to throw it away; it will scarcely repay further attention.
It will be seen that a considerable margin in time of exposure can be allowed and provided for. Yet none the less it is of the utmost importance to learn to give the correct and proper exposure to secure the finest results.
This, it is true, is not always possible, and as an under-exposed plate is lost, any error in exposure would better be in too much rather than in too little time.
It is said by some that by the use of citrate of soda almost any degree of over-exposure may be remedied, but there remains the fact that for a restraining agent to be of any value its application to a negative in development must be almost instantaneous upon the earliest discovery of the over-exposure.
When a large number of plates have been exposed and the first developed indicates that all have been overtimed, then a 50 per cent. solution of citrate of soda, used with judgment, might result in saving the lot.