contact print exposure time

This afternoon, having finally made a negative with proper focus, I
decided to make a contact print. I had never done this before, and I've
got to say it wasn't a lot of fun at first. I read all the stuff on the
web that I could find about making test strips etc..but when I tried it,
all I got was solid black prints. Figuring that I was overexposing, I
searched with no success to try and find out what size of bulb to use
for exposing the paper. In error, I decided that a nice bright bulb
would be the way to go, so armed with a 100watt "cool white" gooseneck
lamp, I boarded up the bathroom (again!) and started to experiment. It
took eight tries to get the first useable print, and that was obtained
by flicking the lamp "on and off" twice with no stop in between. That
print being a bit too dark still, I tried again, and three tries later I
had a very nice useable print (scan to follow). This 100 watt bulb at
about 15" above the glass plate that held the negative and paper flat
took an exposure time of ??? It was just on and off again as fast as I
could flick the switch, almost like a flash bulb. I wonder if any out
there has any experience with "wattage" vs "exposure duration" times and
could lend some advice?

cheers again


--
regards from ::

John Bartley
43 Norway Spruce Street
Stittsville, Ontario
Canada, K2S1P5

( If you slow down it takes longer
- does that apply to life also?)

"John Bartley" wrote in message
m...

This afternoon, having finally made a negative with proper focus, I
decided to make a contact print. I had never done this before, and I've
got to say it wasn't a lot of fun at first. I read all the stuff on the
web that I could find about making test strips etc..but when I tried it,
all I got was solid black prints. Figuring that I was overexposing, I
searched with no success to try and find out what size of bulb to use
for exposing the paper. In error, I decided that a nice bright bulb
would be the way to go, so armed with a 100watt "cool white" gooseneck
lamp, I boarded up the bathroom (again!) and started to experiment. It
took eight tries to get the first useable print, and that was obtained
by flicking the lamp "on and off" twice with no stop in between. That
print being a bit too dark still, I tried again, and three tries later I
had a very nice useable print (scan to follow). This 100 watt bulb at
about 15" above the glass plate that held the negative and paper flat
took an exposure time of ??? It was just on and off again as fast as I
could flick the switch, almost like a flash bulb. I wonder if any out
there has any experience with "wattage" vs "exposure duration" times and
could lend some advice?

When I did contact prints using a similar setup, I placed a 15watts bulb at
about 4 feet from the table and I even added a dimmer switch, so I could dim
the bulb even more to get 20 secs or so of printing time (I did some dodging
and burning sometimes). With exposure times this long you can count (1,
1001, 2, 2002, 3, 2003, etc or whatever you prefer) and have a good idea of
how many seconds of exposure you are giving.

Guillermo

John Bartley wrote:
took an exposure time of ??? It was just on and off again as fast as I
could flick the switch, almost like a flash bulb. I wonder if any out
there has any experience with "wattage" vs "exposure duration" times and
could lend some advice?


The problem is you've got at least a third variable. That is the distance
the bulb is from the paper. 100 watts is likely going to be way too
powerfull unless the bulb is quite distant from the paper. My 4x5 enlarger
uses a 150 watt bulb but the lens can easily be stopped down to F/11. Which
would cut the light by a factor of 128(I think). Use a smaller bulb. BTW I
mean the lens would be F/11 or smaller in use. The lens will stop down
further.

Fourth variable. The paper. Different papers will have different
speeds. I'm assuming you're using an enlarging paper.

Nick

Nick Zentena wrote:

The problem is you've got at least a third variable. That is the distance
the bulb is from the paper. 100 watts is likely going to be way too
powerfull unless the bulb is quite distant from the paper. My 4x5 enlarger
uses a 150 watt bulb but the lens can easily be stopped down to F/11. Which
would cut the light by a factor of 128(I think). Use a smaller bulb. BTW I
mean the lens would be F/11 or smaller in use. The lens will stop down
further.

Fourth variable. The paper. Different papers will have different
speeds. I'm assuming you're using an enlarging paper.

Nick



Hi Nick and Guillermo,

Thank you for the replies. They are EXACTLY what I needed.

Nick, I don't really know what "enlarging" paper is. I am using Ilford
MGIV RC 5x7 in a satin finish. I have never really liked a glossy print,
but I may try glossy paper on my next purchase, and reprint some
negatives just to compare between satin and glossy.

Nick & Guillermo, If I understand what you're saying, the bulb size can
be quite small then I guess, and I gather that up to a certain point
(that point to be determined by experiment) the diminishing amount of
light produced by a smaller bulb can be made up for by increased
exposure times. I guess also that the higher (up to a point) that the
bulb is above the exposure plane, the more even the light is, and will
appear to be perpendicular to the paper/negative combination rather than
be at a slight angle which is what would be seen when the bulb is closer
to the plane of the paper? I would think that there would be some loss
of crispness as you get closer to the paper with the bulb?

Last question : Has any one seen any difference between a coated (soft
white) bulb and a clear glass bulb in the print quality?

cheers

--
regards from ::

John Bartley
43 Norway Spruce Street
Stittsville, Ontario
Canada, K2S1P5

( If you slow down it takes longer
- does that apply to life also?)

John Bartley wrote:


Hi Nick and Guillermo,

Thank you for the replies. They are EXACTLY what I needed.


Ooops - a scan of the better print can be seen at :
http://www3.sympatico.ca/oldrad/Phot...0040702-cp.png

cheers

--
regards from ::

John Bartley
43 Norway Spruce Street
Stittsville, Ontario
Canada, K2S1P5

( If you slow down it takes longer
- does that apply to life also?)

John Bartley wrote:
....

Nick, I don't really know what "enlarging" paper is. I am using Ilford
MGIV RC 5x7 in a satin finish. I have never really liked a glossy print,
but I may try glossy paper on my next purchase, and reprint some
negatives just to compare between satin and glossy.

...

John,

Ilford MG IV RC is an enlarging paper as are most current photographic
papers.

A true contact paper is much slower and you might get away with the
higher wattage bulb with them. Most of them are fiber-based (not RC)
papers. Kodak makes AZO and I believe Bergger or Forte have recently
resurrected a contact paper. (Google Michael Smith for AZO info.)

Another choice is Centennial printing-out-paper (POP), available in both
fiber and RC flavors (from Bostick and Sullivan as well as Chicago
Albumen Works). This paper is similar to the old discontinued Kodak
Studio Proof paper. It can be printed outdoors using the sun or inside
with a strong UV source. The image appears directly with exposure
needing no development. To keep the image from further darkening (which
eventually renders it useless) the paper is rinsed, toned, fixed and washed.

I believe most enlarging papers (developing-out-papers or DOP) will also
produce a printed-out image as well if you follow the same general
procedure as a true POP material. However, I think they must be
loaded/unloaded under safelight conditions into the contact frame
because of their higher speed (unlike POP which can be loaded under
subdued tungsten lighting) and if you skip the development step and just
fix and wash the print, you will have a stable image. I've never tried
this so I don't know if the resulting image would have any quality with
a DOP processed this way. But, my favorite silver paper is Centennial
with AZO second.

You also might want to give the Ilford "pearl" surface a try. The satin
surface never reaches the same maximum dark tone as the pearl or glossy
and thus it appears much lower in contrast and overall weaker in tonal
range IMO. Pearl is in-between satin and glossy in terms of apparent
maximum density and depth. Many people prefer this surface over glossy
since it still has a lustered surface yet lacks the reflecting shiny
smooth surface of glossy RC. BTW, an RC glossy paper has a much more
distractng surface than a similar air-dried fiber-based glossy paper IMO.

Joe

(Change the vOwEl in my email address to reply to me directly.)

"John Bartley" wrote in message
...
Nick Zentena wrote:

Last question : Has any one seen any difference between a coated (soft
white) bulb and a clear glass bulb in the print quality?

I wouldn't use clear glass bulbs, their light distribution is not even.

Guillermo
(also in Ontario)

John Bartley wrote:


Nick & Guillermo, If I understand what you're saying, the bulb size can
be quite small then I guess, and I gather that up to a certain point
(that point to be determined by experiment) the diminishing amount of
light produced by a smaller bulb can be made up for by increased
exposure times. I guess also that the higher (up to a point) that the
bulb is above the exposure plane, the more even the light is, and will
appear to be perpendicular to the paper/negative combination rather than
be at a slight angle which is what would be seen when the bulb is closer
to the plane of the paper? I would think that there would be some loss
of crispness as you get closer to the paper with the bulb?


You normally want longer times so you can do things like dodge/burn the
print. You also want it for your own sanity. With a 20 second exposure if
you screw up and expose for 21 seconds it's not going to kill you. But at
the 1 second range that's 1 second is an issue. The longer times don't
matter until you get much higher.

You can filter the light source if you want contrast control with VC
paper. Or since you're only doing 4x5 contacts I wonder if you could just
put a 6"x6" filter right on top of the negative?

Nick

I would think that there would be some loss
of crispness as you get closer to the paper with the bulb?

Last question : Has any one seen any difference between a coated (soft
white) bulb and a clear glass bulb in the print quality?

I used to do a lot of contact printing of 8x10 negatives and still do some.
I first used a 100 watt interior flood light in a Home Depot flood lamp
fixture suspended about two feet above the paper. My exposure times as I
remember them were in the 15-30 second range using AZO grades 2 and 3 paper.
AZO is a very slow paper made specifically for contact printing so these
times wouldn't be particularly relevant to the enlarging paper you're using.
I later switched to using my enlarger lamp (an Aristo 4500 VCL head) as my
light source becasue it was so much easier to vary the distance of the light
from the paper as needed. I have no idea how many watts that light source
is. However, when turned to maximum blue (since graded papers are most
sensitive to blue light) and with the head 13 inches above the paper and no
lens in the enlarger my times run between 30 seconds and a minute depending
on the density of the negative.

Moving the bulb closer to the paper has no effect on the crispness of the
print. The distance between the bulb and the paper is relevant for two
reasons, it affects the exposure time and it affects how evenly the light is
spread across the print. The closer the light is the shorter the time but
the greater the chance that the light won't be even from edge to edge. The
bulb high should be high enough to spread the light evenly on the paper but
not so high that your exposure times become excessive.

You can check how even the light is by metering the center and the corners
of the paper with your light meter (hand held or in camera, either can be
used). If you don't have a spot meter then you'll need to get close to the
paper, make sure you don't cast a shadow with your body when doing this.
Keep raising or lowering the light and/or increasing or decreasing the
wattage until your meter gives you the same reading at the center and at the
four corners of the paper and results in exposure times of about 20-30
seconds with a normal negative (so that you'll have time to dodge and burn
if necessary).

With graded papers such as AZO there is no difference in the look of the
print with different light sources. A clear bulb presumably would result in
shorter times than a coated bulb of the same wattage but there would be no
difference in how the print looked. However, since the variable contrast
paper you're using is sensitive in different proportions to different
amounts of green and blue light it's possible that different light sources
might have different effects. I'm not sure, I never used variable contrast
enlarging paper for contact printing with a home light source.

"John Bartley" wrote in message
...
Nick Zentena wrote:

The problem is you've got at least a third variable. That is the
distance
the bulb is from the paper. 100 watts is likely going to be way too
powerfull unless the bulb is quite distant from the paper. My 4x5
enlarger
uses a 150 watt bulb but the lens can easily be stopped down to F/11.
Which
would cut the light by a factor of 128(I think). Use a smaller bulb. BTW
I
mean the lens would be F/11 or smaller in use. The lens will stop down
further.

Fourth variable. The paper. Different papers will have different
speeds. I'm assuming you're using an enlarging paper.

Nick



Hi Nick and Guillermo,

Thank you for the replies. They are EXACTLY what I needed.

Nick, I don't really know what "enlarging" paper is. I am using Ilford
MGIV RC 5x7 in a satin finish. I have never really liked a glossy print,
but I may try glossy paper on my next purchase, and reprint some
negatives just to compare between satin and glossy.

Nick & Guillermo, If I understand what you're saying, the bulb size can
be quite small then I guess, and I gather that up to a certain point
(that point to be determined by experiment) the diminishing amount of
light produced by a smaller bulb can be made up for by increased
exposure times. I guess also that the higher (up to a point) that the
bulb is above the exposure plane, the more even the light is, and will
appear to be perpendicular to the paper/negative combination rather than
be at a slight angle which is what would be seen when the bulb is closer
to the plane of the paper? I would think that there would be some loss
of crispness as you get closer to the paper with the bulb?

Last question : Has any one seen any difference between a coated (soft
white) bulb and a clear glass bulb in the print quality?

cheers

--
regards from ::

John Bartley
43 Norway Spruce Street
Stittsville, Ontario
Canada, K2S1P5

( If you slow down it takes longer
- does that apply to life also?)

On Fri, 2 Jul 2004 20:12:20 -0500, Nick Zentena
wrote:

Fourth variable. The paper. Different papers will have different
speeds. I'm assuming you're using an enlarging paper.

Nick

Try Azo . And that 100 watt bulb won't seem so bright.


Regards,

John S. Douglas, Photographer - http://www.darkroompro.com
Please remove the "_" when replying via email