dkw1@hou2a.UUCP (D.WOMBOUGH) (01/10/86)
I have a question for all you netters out there. When I take pictures useing a electronic flash, I get a color shift, gray suits come out blue, and white shirts look blue .I've been told that this was the processings fault, but I have had the same problem with different Labs. Does anyone have a solution or any idea why this my be happening?? Thanks, Dennis Wombough AT&T Bell Labs Holmdel NJ
mfs@mhuxr.UUCP (Damballah Wedo) (01/13/86)
> I have a question for all you netters out there. When I take pictures > useing a electronic flash, I get a color shift, gray suits come > out blue, and white shirts look blue .I've been told that this was > the processings fault, but I have had the same problem with different > Labs. Does anyone have a solution or any idea why this my be happening?? > > Dennis Wombough What kind of film are you using? I think electronic flash is balanced for daylight film. So if you are using film balanced for tungsten light, you will get a pronounced blue cast; tungsten film favors blue to balance out the reds and oranges prominent in tungten light. -- Marcel-Franck Simon ihnp4!{mhuxr, hl3b5b}!mfs " M' kon' you kay lan Boidche`n-nan se' sil-la bel oye' " " Parimach, Nou Yok Taymz, konfidans Nouvelist-o "
howard@sfmag.UUCP (H.M.Moskovitz) (01/13/86)
> I have a question for all you netters out there. When I take pictures > useing a electronic flash, I get a color shift, gray suits come > out blue, and white shirts look blue .I've been told that this was > the processings fault, but I have had the same problem with different > Labs. Does anyone have a solution or any idea why this my be happening?? > > > Thanks, > Dennis Wombough > AT&T Bell Labs > Holmdel NJ The problem is, apparently, with your flash unit. If you are using standard color slide or print film, it is balanced for daylight color temperature (~5500K). If your falsh unit is not properly calibrated for this light temperature the colors on your prints or slide will be off. If the unit is putting out light that is too warm, the results will be yellowish or reddish. If your unit runs cool, like yours seems to be, the results will be bluish. To check out your unit, take it to a camera shop that has a color temperature meter. They will be able to tell you how far off your unit is. The problem then may be corrected wither by repairing your flash or by placing a color correction filter on your flash or over your lens(es). -- --------------------------------------------------------------------- Howard Moskovitz AT&T Info. Systems attunix!howard
dsg@mhuxi.UUCP (David S. Green) (01/13/86)
[] > I have a question for all you netters out there. When I take pictures > useing a electronic flash, I get a color shift, gray suits come > out blue, and white shirts look blue .I've been told that this was > the processings fault, but I have had the same problem with > Labs. Does anyone have a solution or any idea why this my be happening?? In the fifties and early sixties most ( many? ) electronic flash units came with an orange filter that one would slip over the flash when using film that was overly blue sensitive. Is your flash new or old? I thought that most manufacturers of electronic flash equimpment have "warmed up" their flash tubes since the old days. Are you using bounce flash? You can get a tint/cast if you are bouncing off an off-colored wall. Also, outdated film tends to give unexpected color tints. Sounds to me that your flash/film combo is not "warm" enough - get an orange filter for the flash.
kanner@tymix.UUCP (Herb Kanner) (01/14/86)
In article <706@hou2a.UUCP> dkw1@hou2a.UUCP (D.WOMBOUGH) writes: >I have a question for all you netters out there. When I take pictures >useing a electronic flash, I get a color shift, gray suits come >out blue, and white shirts look blue .I've been told that this was >the processings fault, but I have had the same problem with different >Labs. Does anyone have a solution or any idea why this my be happening?? > Two points. First, the color temperature of flash is probably a bit blue compared to daylight. You can probably buy a corrective filter to compensate for this. Second, and I am guessing here, because I do not know the direction of the effect, but there may be an effect due to reciprocity law failure. That is the the failure of a constant value of (light intensity) * (exposure time) to produce a constant effect on the film for extreme cases. By extreme cases, I mean exposures like several seconds or 1/10000 sec. Because the reciprocity failure may be different in the three layers of a color film, this can produce a color shift. It is well-known, for instance, that a ten-second or greater exposure on Kodachrome will tend to produce a greenish image. There may be something to this, because in the early days of (non-automatic) electronic flash, 1/1200 of a second was a common flash duration, and then, a few years later, they all gave about 1/800 sec. However, with automatic flash, the automatic quenching when the subject is close to the camera can give a very short exposure indeed. -- Herb Kanner Tymnet, Inc. ...!hplabs!oliveb!tymix!kanner