Photographer
V-Flat Travis
Posts: 258
Capitol Heights, Maryland, US
I have Rosco Filters: Light Red #26 Orange #23 Primary Green #91 The data sheet only has the transmission value in percentages. Anyone know how to get the compensation value from the percentages? I've talked with Rosco, they couldn't give me the compensation value, was told they didn't calculate them for the 3 filters listed. Forget the reason. The following link, takes you to Rosco's mycolor tool. You can use it to look up the data sheet for any filter Rosco sells, using the number, color name. http://us.rosco.com/en/mycolor Thank You for helping! Travis
Photographer
Zack Zoll
Posts: 6895
Glens Falls, New York, US
Couldn't you just try taking a meter reading with and without the filters and comparing them?
If memory serves, orange is two stops, green and red are three. If it's light red, maybe 2 or 2 1/2.
Photographer
testingphotography
Posts: 218
Seattle, Washington, US
Sorry, you can't assume Orange 2 stops, etc as it depends on the filter. There should be a number on the filter packaging that give the correction. Other wise take a meter reading at a gray card directly and then through the filter. This will be the fixed compensation for that filter regardless of subject.
Photographer
E Thompson Photography
Posts: 719
Hyattsville, Maryland, US
I believe your talking about color gels for lights. Is that correct? If so, a light meter will measure the amount of light reaching your subject with the gels on the light sources. After that, just chimp.
Photographer
Thomas Van Dyke
Posts: 3232
Washington, District of Columbia, US
Rosco Roscolux #26 Light Red Sheet (20x24") Transmission 12%, -3.0 stops
Rosco Roscolux #23 Orange Sheet (20x24") Transmission 32%, -1.7stops
Rosco Roscolux #91 Primary Green - 20x24" Sheet Transmission 7%, -3.8 stops
Hope this helps...
I wish you well on your journey Travis
btw, I left you a comment on your enchanting sunset rendering of two ladies back on October 13, 2014
Lovely narrative...
Photographer
JONATHAN RICHARD
Posts: 778
New York, New York, US
Snaps By Travis wrote:
I have Rosco Filters:
Light Red #26
Orange #23
Primary Green #91
The data sheet only has the transmission value in percentages.
Anyone know how to get the compensation value from the percentages?
I've talked with Rosco, they couldn't give me the compensation value, was told they didn't calculate them for the 3 filters listed. Forget the reason. ..................................... Compensation when using color gels for your lighting is not an exact calculation as there are contributing factors that will affect the saturation of color in your imagery and if these factors are not controlled, will render light meter ratios ineffective for adjusting your color saturation with any reliability. Yet there is a practical test that you can conduct once for each of your color gels that will give you a bench mark ( color saturation chart ) allowing for you to consistently reproduce a range of color saturation for your shoots. This color saturation chart can be used and reused for just about any shoot you conduct to quickly and consistently obtain the color saturation you or the client selects for the shoot.
To do this you must be able to check and then control the relative difference in the amount of light between your background and subject. You will need to first isolate the background from any (visible spill light that will show up either digital or film) . This is where you light meter will be needed.
Once you achieve isolation you can add to the background the correct % of light to achieve the color saturation you desire. Isolation of your background will happen at just over 3 stops difference in relative light between your subject and background.
If you take the time to practical test for your gels to obtain their bench marks (and produce a color saturation chart for each of your gels) you will have an ability to dial in the exact color saturation on your shoots with consistency by selecting the saturation from your color chart and adjusting you light ratio to the value associated for that saturation. Not as exact as a calculation but if your spill lighting is controlled this color saturation chart is just as accurate and consistent for knowing the compensation needed to obtain the desired saturation at any of your shoots …go here
Photographer
Zack Zoll
Posts: 6895
Glens Falls, New York, US
Thomas Van Dyke wrote:
Rosco Roscolux #26 Light Red Sheet (20x24") Transmission 12%, -3.0 stops
Rosco Roscolux #23 Orange Sheet (20x24") Transmission 32%, -1.7stops
Rosco Roscolux #91 Primary Green - 20x24" Sheet Transmission 7%, -3.8 stops
Hope this helps...
I wish you well on your journey Travis
btw, I left you a comment on your enchanting sunset rendering of two ladies back on October 13, 2014
Lovely narrative... Holy crap, I wasn't too far off. Nobody is more surprised than me.
Photographer
Zack Zoll
Posts: 6895
Glens Falls, New York, US
JONATHAN RICHARD wrote:
Compensation when using color gels for your lighting is not an exact calculation as there are contributing factors that will affect the saturation of color in your imagery and if these factors are not controlled, will render light meter ratios ineffective for adjusting your color saturation with any reliability. Yet there is a practical test that you can conduct once for each of your color gels that will give you a bench mark ( color saturation chart ) allowing for you to consistently reproduce a range of color saturation for your shoots. This color saturation chart can be used and reused for just about any shoot you conduct to quickly and consistently obtain the color saturation you or the client selects for the shoot.
To do this you must be able to check and then control the relative difference in the amount of light between your background and subject. You will need to first isolate the background from any (visible spill light that will show up either digital or film) . This is where you light meter will be needed.
Once you achieve isolation you can add to the background the correct % of light to achieve the color saturation you desire. Isolation of your background will happen at just over 3 stops difference in relative light between your subject and background.
If you take the time to practical test for your gels to obtain their bench marks (and produce a color saturation chart for each of your gels) you will have an ability to dial in the exact color saturation on your shoots with consistency by selecting the saturation from your color chart and adjusting you light ratio to the value associated for that saturation. Not as exact as a calculation but if your spill lighting is controlled this color saturation chart is just as accurate and consistent for knowing the compensation needed to obtain the desired saturation at any of your shoots …go here Not to be dismissive, but this seems like a really complicated way to say, "the rating deals with overall transmission, but you're introducing new colors so you're going to have to fuck around a little bit."
Photographer
Retro Wks
Posts: 34
Irvine, California, US
Defining filter compensation is not practically possible, because it depends on the colors you are photographing. The transmission percentages that are specified sometimes apply to calibrated white only. For example, if you have a red pass filter, and you photograph a red object, the filter attenuation is small. However, with that same filter, a blue object would see a high filter attenuation.
Photographer
V-Flat Travis
Posts: 258
Capitol Heights, Maryland, US
Sorry for replying so late. Thank You to all who post a reply. Thomas Van Dyke wrote:
Rosco Roscolux #26 Light Red Sheet (20x24") Transmission 12%, -3.0 stops
Rosco Roscolux #23 Orange Sheet (20x24") Transmission 32%, -1.7stops
Rosco Roscolux #91 Primary Green - 20x24" Sheet Transmission 7%, -3.8 stops
Hope this helps...
I wish you well on your journey Travis
btw, I left you a comment on your enchanting sunset rendering of two ladies back on October 13, 2014
Lovely narrative... @Thomas Van Dyke. I used these as a starting point. Gets me in the ball park, some times. Thank You for the kind words on my work.
E Thompson Photography wrote:
I believe your talking about color gels for lights. Is that correct? If so, a light meter will measure the amount of light reaching your subject with the gels on the light sources. After that, just chimp. @E Thompson Photography. I just ended up adjusting the color to taste.
Thank You all for the kind words.
Photographer
Znude!
Posts: 3317
Baton Rouge, Louisiana, US
Lee filters actually has two free apps for calculating filter exposure compensation (don't remember about color). I use them all the time. They are fast and easy and while not always a hundred percent accurate they can get you into the ballpark quickly for exposure. Find them on their website, ProGlass and LeeStopper. Found this for color. http://www.leefilters.com/lighting/mire … lator.html They also have a comparison to other brands of filters. Don't know if any of this helps.
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