OT photography question.

I am asking this here because I know some of you are very knowledgeable
on the subject. I want to take digital photos of black and white
drawings with red and green pencil markups. The reds and greens are
not bright.
So far I can get the resolution I need but the reds and greens don't
show up so great. I think the problem is in the spectrum of the light
i am using. I have tried the flash on the camera, fluorescent
lighting, and sunlight.
I am going to build a stand to position the camera over the drawing (or
part of it). I will add lighting fixtures to the stand to get the
quantity of light but the quality of the light. I can get what ever
will work (metal halide, Ott lights, quartz etc.)
If you can suggest a better group I'll take it there, I found about 900
hundred photography groups.
Any way this has noting to do with who Cheny shot or Lie, Spin and
Deny.

BJ Conner wrote:
I am asking this here because I know some of you are very knowledgeable
on the subject. I want to take digital photos of black and white
drawings with red and green pencil markups. The reds and greens are
not bright.
So far I can get the resolution I need but the reds and greens don't
show up so great. I think the problem is in the spectrum of the light
i am using. I have tried the flash on the camera, fluorescent
lighting, and sunlight.

Does your camera have a control that lets you increase the color
saturation? If so, try it.

Try getting the best photo you can and then enhance the reds and the
greens with Photoshop or some similar software.

--
Cut "to the chase" for my email address.

Lighting would have been the first thing I would have experimented
with, but it sounds as though you've been there, done that. If you're
not getting true color even with sunlight, I'd suggest trying different
exposure settings on the camera. Most digitals above the bottom end
have at least a brightness adjustment, and it may be a simple as that.
For subtle colors, it's often a fine line between dark and washed out.
If you have saturation adjustment, all the better. At worst, see what
you can do with PhotoShop afterward.

Joe F.

BJ Conner wrote:
I am asking this here because I know some of you are very knowledgeable
on the subject. I want to take digital photos of black and white
drawings with red and green pencil markups. The reds and greens are
not bright.
So far I can get the resolution I need but the reds and greens don't
show up so great. I think the problem is in the spectrum of the light
i am using. I have tried the flash on the camera, fluorescent
lighting, and sunlight.
I am going to build a stand to position the camera over the drawing (or
part of it). I will add lighting fixtures to the stand to get the
quantity of light but the quality of the light. I can get what ever
will work (metal halide, Ott lights, quartz etc.)
If you can suggest a better group I'll take it there, I found about 900
hundred photography groups.
Any way this has noting to do with who Cheny shot or Lie, Spin and
Deny.

I know thqt with a film camera I would try a trick called "reciprocity
failure". Basically, you use a slow shutter speed and a tight aperture.
The film is exposed for so long that the colors shift in a very
interesting way. Don't know if there is a digital analogy to that.

Peter Collin

On 17 Feb 2006 11:54:35 -0800, "BJ Conner"
wrote:

I am asking this here because I know some of you are very knowledgeable
on the subject. I want to take digital photos of black and white
drawings with red and green pencil markups. The reds and greens are
not bright.
So far I can get the resolution I need but the reds and greens don't
show up so great. I think the problem is in the spectrum of the light
i am using. I have tried the flash on the camera, fluorescent
lighting, and sunlight.
I am going to build a stand to position the camera over the drawing (or
part of it). I will add lighting fixtures to the stand to get the
quantity of light but the quality of the light. I can get what ever
will work (metal halide, Ott lights, quartz etc.)
If you can suggest a better group I'll take it there, I found about 900
hundred photography groups.
Any way this has noting to do with who Cheny shot or Lie, Spin and
Deny.


As far as lighting goes, your lights should be positioned at 45 degree
angles either side of the camera with the paper on a flat surface and
the camer three dimensionally perpendicular to it. The 45 degree
angle generally eliminates glare and gets the best colour saturation.

When using different types of lights, you'll get a different colour
temperature that can be compensated for via the white balance control
on your camera. Be careful to use lights meant for colour photography
as some types of lights can be missing part of the light spectrum.
Our eyes/brain adjusts for colour temperature and missing spectrum but
the camera can't. It records what it sees. White balance control is
probably your best bet.

Second problem comes from the curse of digital photography --
automation. No idea on the ratio of black to white on your drawings
or the metering pattern of the camera but odds are, your image is more
white than black so it's not close to 18% reflectance of the grey
scale calibration of camera meters. As a consequence, your image is
probably underexposed. That'll muddy up the colours, fer sure. If
your camera can bracket, shoot from 2 stops under to 2 over in half
stop increments and you'll probably can get one that's perfect. I
realize colour/contrast/brightness/gamma etc. can be adjusted in
software but nothing beats getting the right exposure.

HTH

Peter

turn mailhot into hotmail to reply

BJ,

I'd repeat what Peter just said and that you can also try using a "light
tent" to help diffuse the light a little. Glare can really kill contrast
when the light is from a point source. A plain white sheet hung between the
lights and the object being photographed can do wonders (don't get so close
you start a fire). Also use a lens hood, to keep the light from entering the
lens other than what's being reflected by the subject.

Peter's best advice was to bracket the exposure by at least two stops. In
fact, if you are comfortable with overriding the auto systems on the camera,
try going to 3 or even 4 stops over exposed from a white metered surface.

If you have something like Photoshop Elements or Paint Shop Pro, try
adjusting the brightness and contrast both to the higher end of the scale.
You can also turn up the saturation, if what you need is for the colors to
become more visible.

If you want to add people to your killfile, try asking on alt.photography.
Just remember that some people are willing to help and others are only
willing to be obnoxious.

Another thought I just had was that if this is truly flat surface, put it in
a color scanner/all-in one and see what you can get. Even that can be "post
processed" if you need to do so.

Mark

My gratitude to all of you that took the time to answer.. I knew this
was the place to ask the question. The knowledge that resides in this
group is phenomenal. All good answers and I shall investigate them
all. I had not though of taking the glare off the lighting, that will
be a first step.
The camera and the one that will replace it has a myriad of setting and
adjustments one can make. It's time to read parts of the manual I
just skipped through the first time.
Mark, these are "E" size drawings, so far scanners for them are to
delicate and spendy. The camera has the resolution to capture the
detail, I wasn't getting the color quality I wanted.
So it's to the manual and read. The thing has more buttons than a
Russian Calvary officer's tunic. Actually three or four that let you
drill down and down.
Thanks again for the help and the confirmation that this is indeed a
fine group.

Peter A. Collin wrote:

I know thqt with a film camera I would try a trick called "reciprocity
failure". Basically, you use a slow shutter speed and a tight aperture.
The film is exposed for so long that the colors shift in a very
interesting way. Don't know if there is a digital analogy to that.

Reciprocity failure doesn't happen with digital cameras, but noise can
be a problem with long exposures.

--
Cut "to the chase" for my email address.

My stab at a light tent:

http://montana-riverboats.com/Pages/...Lights_On.html

wrote:
My stab at a light tent:

http://montana-riverboats.com/Pages/...Lights_On.html
Thanks, illustrates the ideal quite nicely.