Re: colorsync-users digest, Vol 3 #192 - 15 msgs
Re: colorsync-users digest, Vol 3 #192 - 15 msgs
- Subject: Re: colorsync-users digest, Vol 3 #192 - 15 msgs
- From: "Joseph A. Castay" <email@hidden>
- Date: Fri, 3 May 2002 14:35:14 -0300
Hi Steve,
Here are some thoughts about camera profiling. Let's assume for the
moment that:
Each camera is unique. Each strobe is unique. Today many photographers
have multiple cameras. They have always had multiple strobe heads
(bulbs). Film is crafted to respond to a specific light temperature plus
or minus some Kelvins. CCD is crafted to respond to a specific light
temperature plus or minus some Kelvins.
So the questions is how do you balance for any given situation?
Profiling a CCD: A profile is a characterization of how the CCD
reproduces/records information. Not a calibration of the device. It is
recommended that you follow the manufacturers guidelines for
calibration.
Profiling film: Using a densitometer, the film can be measure. The
measurements are compared to existing values. Create a plot then make
adjustments chemically, light, filter, etc.
A profile is device and substrate specific, and in the case of cameras a
profile is environment specific, in or out of the studio. This means you
can have 1 really great 5000K general profile for day or strobe (a tough
one). Or a specific profile for each environment (better).
Traditional and digital photography differ, but traditional techniques
will always be applied to digital photography in some fashion.
Create your workflow:
1) Camera, main light source (could be more then 1 unit), [this ex.
5000K]
2) Now ADD light, white, tungsten. gel colored, UV Filtered, and so on.
3) What is going to happen? Simple? -Maybe. The image will be biased to
the main light. Any other light source no matter what the Kelvins will
create a cast, good or bad.
4) Problem: If this color cast (regardless of Kelvin) is troublesome
then you will need to adjust the light source causing the cast. Have a
color meter?
Now do this digitally:
Now do this digitally with profiling:
Steps 1,2,3,4 may still apply. (Digital you can see values that you
would not have noticed on film with the ole eyeball.)
Your dealer/systems integrator should be able to show you how to do
this. If not give me a call.
In a similar situation I apply one or two tradition techniques to
digital printing.
Editing input profiles:
I do not prefer to edit an input profile. However, I will on certain
occasions. Typically, edits are small and are for that specific
circumstance (not necessarily major ones).
So why do you profile your input devices. This is very straightforward:
You do so because you want to get the most out of your CCD. The camera
in the box is rarely at its best performance. You want to feel confidant
that you can expect X results. Because even though the output is going
to dispose of much of the color, you want the output to have the best
selection of color to choose from, resulting in a higher quality output.
Time, consistency, flexibility, production, saving money, etc.; you can
throw that stuff in there too.
Want to make all your deferent digital cameras to look the same, you
need to edit your input profiles and likely sacrifice something, (maybe
noticeable - maybe not). Or create an action to make conversion
adjustment. (good for batching).
Joseph A. Castay
978-388-8008
email@hidden
On Friday, May 3, 2002, at 02:13 AM, colorsync-users-
email@hidden wrote:
>
>
"Subject: Camera profiling
>
A concern I've always had with this idea is the
>
strobe/light color temperature and response of the camera chip. If we
>
profile one back to Broncolor strobes and then use Speedotron location
>
strobes, what are we doing to the captured files once we gray balance?
>
For
>
that matter similar make strobe heads vary in color temperature. In the
>
old, old, old days... I used a color meter and corrected each strobe
>
to a
>
known film emulsion."
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