yellow gold tint, and brought by the bromine to a very light, rose color,
have their whites very intense, and their deep shades very black.
It is also known that if you employ a thicker coating of iodine and apply
upon it a proportionate tint of bromine, so as to obtain a deep rose tint,
delineations will be less marked, and the image have a softer tone.
This effect has been obvious to everyone who has practised the art.
Thus I may observe that the light coatings produce strong contrast
of light and shade, and that this contrast grows gradually less,
until in the very heavy coating it almost wholly disappears.
From this it will readily be perceived that the middle shades are
the ones to be desired for representing the harmonious blending
of the lights and shades.

Then, if we examine, with respect to strength, or depth of tone, and sharpness
of impression, we see that the light coating, produces a very sharp but
shallow impression; while the other extreme gives a deep but very dull one.
Here, then, are still better reasons for avoiding either extreme.
The changes through which the plate passes in coating may be considered
a yellow straw color or dark orange yellow, a rose color more or less
dark in tint, or red violet, steel blue or indigo, and lastly green.
After attaining this latter color, the plate resumes a light yellow tint,
and continues to pass successively a second time, with very few exceptions,
through all the shades above mentioned.

I will here present some excellent remarks upon this subject by Mr. Finley.
This gentleman says:

"It is well known to all who have given much attention to the subject,
that an excess of iodine gives the light portions of objects with
peculiar strength and clearness, while the darker parts are retarded,