Is the quick battery of the right strength?
If dry, it must change the plate in from six to fifteen seconds.

If any of the chloride of iodine class, it may vary from five seconds to a minute.

Begin by coating light, and increase on each trial, observing the effect.

If the light side of the picture seems loth to come out, and shows no contrast with the dark side, it is to be inferred that your battery is too strong, and must be reduced with water or set out in the open air for a few minutes, with the lid off.

If working an old battery, never renew very strong, or it will work dark and heavy.