....Ebony and Ivory....together in perfect harmony...side by side by my
piano keyboard...zzzzzzzz.

Yes, this makes sense.  But the rest probably not too dark...the reflected
safelight will help in navigating the semi-darkness.  

<< If your darkroom is "light tight" then it doesn't matter what color it is
since it can't reflect light if there is none.  However it might be safer to
keep the area within about four feet of your enlarger black to avoid
reflections off the wall from your enlarger onto the paper

Flat black on the wall and ceiling near the enlarger -- white
everywhere else.

Chris Ellinger
Ann Arbor, MI

There are several sources of 'stray light' (light you don't
want) when enlarging:

1) Light leaking from the enlarger

   a) negative carrier
   b) lamp housing
   c) lens board or lens turret

2) Light leaking (not quite the right word) from the lens

   a) internal lens reflections (not a big deal w/ coating)
   b) Imaging of inside of the lit (by the negative) portions
      of the lens bellows/cone and negative carrier.  If possible
      twist your head and take a look up the lens - scary.

3) Light reflected from the paper, illuminating the room,
  especially the ceiling and hence the paper.  If you have
  a white ceiling take a look up when enlarging.

The result is that the whole area around the enlarger is well
illuminated with white light - if your darkroom was this light
you _know_ your paper would fog.

The effect is variable:

The effect from (1) is proportional to the exposure time and
negative density - the amount of fogging light is constant and
the longer the exposure time the more fog.

The effects of (2) may change with head height as more of the
light falls on the enlarger column or room walls.

But generally the fog from (2) and (3) are constant for all
negatives and magnifications: they are proportional to the
amount of light-seconds to expose the paper which, if
paper sensitivity is fixed, is generally constant.

In sum, just about all the fogging light hitting the paper
first bounces off the ceiling and walls.  Painting them
black will reduce the amount of fog.  (3) light from the
enlarging paper, and often the greatest contributor, can
only be mitigated by painting walls and ceilings black.
Reducing (2b) requires a bit of flocking/painting inside the
enlarger.

Now, how much does this matter?

If you are making murals you will find it is almost
impossible to get clear highlight.  The light leaking
from the enlarger, that has no effect in a 20 second
exposure, fogs mightily in a 10 minute exposure.  Also
the entire darkroom becomes the enlarger's cubicle and
would need to be painted black to keep fog down.

Can you see it?  Do you care?  Only one way to find out:

1) put a clear negative in the carrier, place
  two overlapping coins/opaque things in the
  center of the paper.

2) make a middle grey exposure

3) place a coin on the center of the clear film in
  the carrier.  The coin should not cover more
  than 1/3 the negative area.

4) Remove one of the coins in (1)

5) Make another exposure equal to (2)

6) Develop

7) Any difference between the overlapping coins is the
  highlight effect.  Any difference in the shadow of
  the removed coin is the mid-tone effect.

Good point.  The darkrooms at the Cleveland Museums are painted yellow,
NTITOI.

And one could certainly get away with red for the walls around the
enlarger.  Make life a bit brighter.  Here in Cleveland we need
all the bright we can get.

I have a client with dark blue darkroom walls, it's the corporate
color, and combines the blue with deep red safelights.  With the
white lights off the walls go to dead black.  As it is like working
in a cave and so they need to have lots and lots of safelights to
make up for it, but then they make safelights.  I suspect the
corporate blue reflects UV very well, but it is polite not to
press the issue.

It's not necessary to paint the wall black around the enlarger if the rest
of the room is painted white: just paint some panels flat black and place
them around the  enlarger area when you're working with the enlarger of an
evening.

-
-----------------------------------------------------------
les clark / edgewater, nj / usa
-----------------------------------------------------------