Color correction filters for transparency film?

[shutterboy]

Hello,

Do large format landscape photographers, shooting mostly slide film stocks, use spectrometers and color correction filters? If yes, then under what scenarios?

I am specifically asking about correcting color casts and not the typical warming/cooling scenarios when using (for example) tungsten film in daylight or vice versa.

Thanks

[Joe O'Hara]

I don't know of anyone who uses a spectrophotometer but some landscape photographers who do color work in the woods use a .05 magenta filter to take out
the green tinge that the light picks up from passing through the trees.

[Dan Fromm]

OP, I think you mean color meter, not spectrophotometer.

I've never met or known anyone who admitted to owning a color meter, let alone using one. But there are quite few on offer on eBay.

I've hit situations out-of-doors where one and a good set of CC filters might have been useful.

For one, I once took a picture of an alligator in the Big Cypress. Fairly early morning, deep shade, ISO 100 Ektachrome, I forget which one. 35 mm, not LF, not that it matters. In that situation roses may be red but 'gators are blue. Bright blue on the Ektachrome I used.

For two, I was once doing acceptance tests on several old uncoated lenses. Out of doors, ISO 100 Ektachrome, 2x3 on 120 film, not LF, not that it matters. Same subject for all shots. One lens' shots were all very blue. I retested, got the right colors as expected. The blue wasn't due to the lens, an f/6.3 B&L Tessar. I'd shot its several test shots (f/11, f/16, f/22, the apertures I most often use) with the sun behind a cloud. The other shots in the first series were taken with the sun not behind a cloud.

Shadows are blue. Early morning and late afternoon sunlight is very yellow. I've never felt the need to get a color meter and filters to fit my lenses to detect and correct the conditions. But that's me. You have to decide what will and won't work for you.

[shutterboy]

OP, I think you mean color meter, not spectrophotometer.

You are right. I meant to type spectrometer. I am a physicist and deal with a lot of spectrophotometry. So I guess it was more of muscle memory. I have fixed it in the original post.


I've never met or known anyone who admitted to owning a color meter, let alone using one. But there are quite few on offer on eBay.

I made an amazing decision of marrying a terrific girl about 10 years ago. She happened to approve a good amount (in my opinion) of money for my birthday on account of not pulling strange stunts in the past year. Therefore here I am to ask. :D


Shadows are blue. Early morning and late afternoon sunlight is very yellow. I've never felt the need to get a color meter and filters to fit my lenses to detect and correct the conditions. But that's me. You have to decide what will and won't work for you.

Thank you so much for sharing your experience. It is very nice of you.

[Bob Salomon]

You are right. I meant to type spectrometer. I am a physicist and deal with a lot of spectrophotometry. So I guess it was more of muscle memory. I have fixed it in the original post.



I made an amazing decision of marrying a terrific girl about 10 years ago. She happened to approve a good amount (in my opinion) of money for my birthday on account of not pulling strange stunts in the past year. Therefore here I am to ask. :D



Thank you so much for sharing your experience. It is very nice of you.

If you are going to get a color meter make sure that you get a 3 color one, not a 2 color meter.

[Mark Sampson]

Twenty-plus years ago, commercial photographers made their living by delivering perfectly-exposed, perfectly-colored transparencies to the client. This required careful and regular emulsion testing, as well as an accurate and consistent E-6 process. The results of which might result in adding a 5Y + 2E (say) to the camera lens to ensure correct color. And a good deal of angst along with a fair amount of "sturm-und-drang" at the lab; been there, seen it.
That level of lighting consistency isn't really possible in the field; I suppose a color meter and a set of color-correction gels might help- but will it be worth the extra expense and effort? Perhaps, if your end product is chromes viewed on a 5000K light box. If you plan to make prints, then today the workflow requires scanning and an image-editing program, which is a much more flexible way of dealing with color inconsistencies. Getting it right in the camera is a noble goal, I admit...

[Eric Leppanen]

If you can get hold of a July/August 2005 copy of View Camera magazine, Charles Cramer wrote an excellent how-to article on this subject. He recommended a Gossen ColorPro 3F color meter and a set of warming filters (he used an 81A, 81C, 81EF, 85C, and 84) for use when photographing under open blue skies in complete shade or prior to sunrise or after sunset. Back in the day I went in whole hog and picked up a used 3F meter and a set of filters (I settled upon an 81A, 81B, 81C, 81EF and 85C) which used singly or in combination covered all the lighting scenarios I expected to encounter. But unless you have your heart set on viewing fully color corrected chromes on a light table, in our current Lightroom/Photoshop scanning/printing era in-camera color correction is largely superfluous, as you can warm up your images to taste on your computer monitor. Color correction can be more accurate if you actually measure color temperature at the time of exposure, but for field landscape work no one really needs this level of accuracy.

Since I still carry a set of color filters for B&W photography, I've kept my warming filters which once in a rare while I still use. If anything I find them most useful with color neg film, since it is already challenging to get the colors right when scanning and inverting color neg images, even with modern software tools such as Color Lab Pro. But for most folks lugging along a full set of warming filters addresses an extremely limited use case. They are useful only in full shade under open blue sky (they cause more harm than good in mixed lighting, and are unnecessary under overcast), and getting a reasonable color temperature reading with a color meter in the field takes practice. Light is typically reflected from a wide variety of nearby objects, and subtle changes in the orientation of the meter can produce significantly different readings. I usually take several readings in the general direction of an open sky light source, then generally go with the least measured correction, as I'd rather err on the side of too little correction than too much (e.g. yellow vegetation is not a fetching look). If you are in a deep canyon, for example, a warming filter may not be needed at all since the canyon walls will reflect warm light on your shaded subject even if you are under open blue sky.

[Bernice Loui]

Go to post# 20 on this link:
https://www.largeformatphotography.info/forum/showthread.php?155445-Easy-Testing-Used-LF-Lenses/page2&highlight=elinchrome

IMO, trying to achieve this degree of color balance on color transparency film today is not possible. Trying to achieve this outdoors is going to be near not possible at all due to the vast changes and differences in color temperature of sunlight over the course of the day. Sunlight's color temperature varies by time of day (sun rise-noon-sun set), altitude, direct sun, shade and a long list of other factors.

Best of the color temperature meters from that era was the Minolta flash color meter III , owned and used one back in the day. It is accurate, easy to use and reliable. If you're really curious about shift in lighting color temperatures, get one that is in good accurate condition, then check sunlight color temperature over the course of a passing day.

Second item needed, a GOOD set of "Color Correction" or cc filters. These are used to achieve color balance after the color transparency or other color film has been tested for color balance at a specific lab's processing chemistry and system.

The entire business of achieving color balance to this degree was very common for commercial ad marketing work as that market demanded high quality images back then. In comparison to outdoor land scape color images where Fuji Velvia has become quite popular.. Fuji Velvia is NOT a color accurate film, it has stylized color rendition. Fuji Astia IMO was one of the best color transparency films for accurate color rendition and moderate contrast was one of the best made. Astia was quite un-popular with many image makers even back then.


Bernice

[shutterboy]

Very insightful.


Perhaps, if your end product is chromes viewed on a 5000K light box. If you plan to make prints, then today the workflow requires scanning and an image-editing program, which is a much more flexible way of dealing with color inconsistencies. Getting it right in the camera is a noble goal, I admit...

My end product is definitely prints. But I have seen that it is very hard to correct the colors after the fact. I have had some help with using something like a Xrite passport checker (https://www.xrite.com/categories/calibration-profiling/colorchecker-classic-family/colorchecker-passport-photo-2), but still sometimes it seems something is amiss.


If you can get hold of a July/August 2005 copy of View Camera magazine, Charles Cramer wrote an excellent how-to article on this subject. He recommended a Gossen ColorPro 3F color meter and a set of warming filters (he used an 81A, 81C, 81EF, 85C, and 84) for use when photographing under open blue skies in complete shade or prior to sunrise or after sunset. Back in the day I went in whole hog and picked up a used 3F meter and a set of filters (I settled upon an 81A, 81B, 81C, 81EF and 85C) which used singly or in combination covered all the lighting scenarios I expected to encounter. But unless you have your heart set on viewing fully color corrected chromes on a light table, in our current Lightroom/Photoshop scanning/printing era in-camera color correction is largely superfluous, as you can warm up your images to taste on your computer monitor.

Oh my goodness. How could you possibly refer to something that was published 15 years ago. I have trouble with remembering things that happened 15 days ago. I was thinking of gradually buying the entire CC set from Lee. But after listening to other folks here, I will probably not go that route. You mention


Color correction can be more accurate if you actually measure color temperature at the time of exposure.

So, let's say, I make a measurement right before the exposure and the meter tells me I am at 3300K. I am using something like Provia 100 (say) or Ektar (negative, I know). These are daylight balanced, so 5500K. How should I compensate in post processing armed with this information?


Second item needed, a GOOD set of "Color Correction" or cc filters. These are used to achieve color balance after the color transparency or other color film has been tested for color balance at a specific lab's processing chemistry and system.

I process my own E6 using Fuji Hunt 5L kits in a Jobo rotary tube processor. I pay close attention to pH and Sp Gr of the chemicals and run a tight (in my opinion) process control. I understand that you mentioned Velvia 50 is NOT a color correct film. Knowing that, do you think that as per Dan Fromm's blue alligator experience (third post from top), such things might throw off exposures due to light with color cast?

[Bernice Loui]

Home processing, not even close. The New Lab had a full time Chemist to assure the E6 chemistry was consistent and reliable day after day, week after week, month after month. They used a Refema dip-dunk system that can push-pull in 0.1 f-stop increments if needed. To get that level of consistency and reliability in E6 processing is no small matter and seriously questionable for home E6 processing using E6 chemistry kits.

Color cast out doors is often due to differing color temperatures, reflected colors and a very long list of variables. This is why back in the day, consistent and accurate color was achieved by high quality strobe light, tested then tweaked as needed. Notable is how the cinema or big budget film folks deal with the color shift problem out doors, they do color temperature meter the light and add cc filters as needed based on testing done on film, for some scenes they will bring in BIG lighting to gain control of the lighting. These folks mostly know precisely the visual presentation they are after and how to achieve it.

As preciously mentioned, if you're serious about this, get a Minolta Flash III color temperature meter, learn how to use it and apply the tools (cc filters film testing, color densitometer and all related) as needed.

All that said, it does depend on your specific image goals and needs... which is complex and only you can decided how far to go to achieve this.


Bernice




I process my own E6 using Fuji Hunt 5L kits in a Jobo rotary tube processor. I pay close attention to pH and Sp Gr of the chemicals and run a tight (in my opinion) process control. I understand that you mentioned Velvia 50 is NOT a color correct film. Knowing that, do you think that as per Dan Fromm's blue alligator experience (third post from top), such things might throw off exposures due to light with color cast?

[Dan Fromm]

OP, you identified yourself as a physicist. Bad move.

Do you remember the SSC that was never built? The magnets were to be powered by homopolar generators. Six of them, if I recall correctly. The physicists who designed the SSC designed them too, sent their designs out for bids. The company my father worked for was asked to bid. He was responsible for the proposal. Turns out that the designers had optimized everything, including bearings and fasteners (nut and bolts, mainly). My father calculated that the project budget would cover the cost of making one (1) generator because all of the bearings and fasteners were custom and, therefore, very expensive. He spent more time convincing the physicists that standard bearings and fasteners, chosen to be no worse than the optimal ones they' designed, would make the six generators needed fit inside their budget than on the rest of the proposal. My father was an engineer, ChemE actually, not MechE. He complained bitterly to me about theorists' ignorance of, um, reality.

You're overthinking the problem. Get a color meter, pick an E6 emulsion or several and processing protocol and then go out and test. Measure the color temperature, shoot, process and decide whether the results are tolerable. Repeat under different circumstances, and especially repeat the measurements to find out how variable conditions really are. Then you'll know enough to decide whether a set of CC filters is worth the bother and expense.

[shutterboy]

OP, you identified yourself as a physicist. Bad move.
He complained bitterly to me about theorists' ignorance of, um, reality.

You're overthinking the problem.

That is a great summary of my general problem. Very well said sir. Thank you. I really appreciate it. :)

[Eric Leppanen]

So, let's say, I make a measurement right before the exposure and the meter tells me I am at 3300K. I am using something like Provia 100 (say) or Ektar (negative, I know). These are daylight balanced, so 5500K. How should I compensate in post processing armed with this information?

In my experience cooling temperature adjustments (such as 3300K to 5500K) are very, very rarely encountered when shooting landscapes in the field. The warm, soft light just after sunrise and just before sunset (commonly called the "golden hour" although in reality it lasts more like 15 minutes) is traditionally highly valued by chrome landscape photographers for its rich colors, low angle of light (for dramatic shadows and an enhanced sense of depth) and reduced contrast which helps fit the scene within the extremely limited dynamic range of chrome film. Color correcting this warm light in the name of theoretical color accuracy would be unthinkable to most folks. Landscape photography usually presents an interpreted, often idealized version of the world, not a technically accurate one.

One of the most common color adjustments is warming up colors in shadows, which most film emulsions to various degrees render with a blue cast. Provia is notorious for this, and even color neg film can go notably blue in shadows in challenging scenes.

Photoshop has a facility for making your own color balance adjustments. It can also simulate the effect of different warming and cooling filters. See:

https://helpx.adobe.com/photoshop/using/applying-color-balance-adjustment.html

In your example you could select the 80 cooling filter for a global effect, which would be the closest match to your desired 3300K to 5500K correction. In mixed lighting scenarios (such as correcting blue Provia shadows in an otherwise mostly sunlit scene) you could manually adjust the color balance to warm the shadow areas only, leaving the midtone and highlight areas alone. In this latter scenario you would be warming to taste, rather than trying to precisely nail some exact correction in terms of kelvins.

[Alan Klein]

Blue casts might be more prevalent at higher altitudes where ultraviolet rays are more intense as well as the blues.

[Bob Salomon]

Blue casts might be more prevalent at higher altitudes where ultraviolet rays are more intense as well as the blues.

Also,in the sun in snow fields and high altitude shadows.

[shutterboy]

Blue casts might be more prevalent at higher altitudes where ultraviolet rays are more intense as well as the blues.


Also,in the sun in snow fields and high altitude shadows.

Have you used any mechanism to compensate for these casts? Did you use a color meter for this?

[LabRat]

There's other factors too... Though you are at the mercy of time of day and atmospheric conditions, these are generally forgivable as our eye also sees these (like warm light late and early in the day, haze etc)...

Our in-process concerns are if the film is picking up unnatural casts where we know the color well but contaminates it (white clouds, neutral colors like middle greys, flesh tones, white surfaces etc)... Newer film is usually very good shooting in light balanced for it (daylight), but other issues can creep in...

First, is exposure level, as chrome film has little tolerance for exposure errors (esp underexposure) that can exaggerate mild color casts...

2nd is processing, where depending on the lab, condition of chems, temp maintained etc can introduce casts... These can be corrected somewhat, but are they consistent in each processing run???

Then there's printing... Do the casts show up in the final output, or do you have some control to correct them??? If the chromes are just being scanned, you have wiggle room... I don't think there is is fresh Type R paper or chem now produced, so that's out... So film will typically be scanned now...

Brush up on exposure methods, shoot some fresher film of subjects with familiar neutrals in it, decide who will process E6 film (and if consistent), and get the film on a good lightbox to see how it turned out... If any casts, they should be subtle and natural looking... For different than normal conditions, use of the recommended filter should do the trick... Other minor CC changes are often from the process itself...

A good exercise would be to shoot some smaller format chrome films again to re-aquant one with how chromes will shoot under different conditions...

But I would recommend color negative film to shoot for LF, as there is more latitude, is more forgiving, and more printing options for it...

Steve K

[Alan Klein]

Have you used any mechanism to compensate for these casts? Did you use a color meter for this?

I have an 81B warming filter but haven't used it in years.

[unityofsaints]

But I would recommend color negative film to shoot for LF, as there is more latitude, is more forgiving, and more printing options for it...


Yes but the look on a light table is not even half as satisfying :)

[LabRat]

Yes but the look on a light table is not even half as satisfying :)

Yes, with a good chrome, but if not perfect, a neg will provide some breathing room... ;-)

Steve K

[LabRat]

In smokey areas these days, better have some heavy cooling (barely used) 80C daylight to tungsten conversion filters!!!

Steve K

[Drew Wiley]

I love the amber light of this smoke. Makes me feel like I'm in a Godfather movie. I just don't want to be out breathing it.
Chrome films results are easy to judge over a good light box. I used a color temp meter and cc filters only for making master transparencies to calibrate batches of color paper and related critical lab purposes, or under artificial indoor lighting situations when there was a mismatch. It's been a long time since batch variation in chrome films themselves carried recommended starting filter corrections on the box, and even then, landscape photographers largely ignored that. Many even liked the way old style Ektachrome 64 especially exaggerated blues when uncorrected.
Color neg film is a different story, and especially the one I use most, Ektar. I have a selection of corrective filters I routinely carry for that in order to counteract potential cyan crossover in shadows and overall balance issues. I don't carry the color temp meter with me because I already know what to expect from previous testing and printing experience. This particular CN film is designed to give a more balanced saturated look similar to chrome films, so isn't artificially warmed like portrait-friendly ordinary color neg films.
My routine default filter is a Hoya light pink 2A skylight filter for minor overall correction. If there's bluish cold overcast, I use a slightly stronger pink-amber Singh-Ray KN (which is a bit better than a KR1.5, which in turn is a bit redder and better than an 81A; but all are usable for this situation). I rarely use an 81B, but do sometimes use a special Tiffen filter which behaves like an 81B and 2A combined, which helps balance out the cyan over-reaction to what are in fact blue shadows in open sun situations; otherwise, a KR3 is preferable to an 81C in similar conditions; but I own them all for slightly different reasons. I even made a couple of special flashing attachments for differentially correcting shadow versus highlight conditions in open sun, but they're clumsier and less predictable to use. The only cc filter I use in the field is an 05M for selectively cutting green out of the blues, and hence the risk of cyan crossover. Of course, I never carry ALL these filters at the same time, just a few I anticipate needing for specific conditions.

[tgtaylor]

I don't believe that it is necessary to use a filter with color negative film as you "color correct" when printing. Back in '97 when comet Hale Boop was at its brightest I shot an eyepiece projection photo of the comet's very active nucleus on color negative film with a K1000 camera and had it processed and printed at one of those ubiquitous one hour photo labs. The resulting print was all an all green comet and didn't show the structure of the nucleus which was very dynamic in the eyepiece. This was before my film printing days and I showed the print to Dr. Fraknoi at Foothill college who, at the time, gave popular public lectures on astronomy. He couldn't (or wouldn't?) explain the color either. Now, of course, that should be an easy color correction in the enlarger. If you ever get the chance, do observe the nucleus of a comet through a high power eyepiece - I believe that I was using a 25mm eyepiece on 10" f10 telescope.

[Heroique]

Do large format landscape photographers, shooting mostly slide film stocks, use [color meters] and color correction filters? If yes, then under what scenarios?

I've used a Sekonic color meter at Glazers Camera in Seattle (their meter) to test B+W's 10-stop ND filter – which had been proving in my experience to be anything but "neutral" in the field for transparencies. (I often use this 52mm filter with my Fuji A 240mm/9 and Schneider 150mm g-claron with thread adapter.)

The goal was to determine what single filter might bring the B+W back to "neutral."

According to the Sekonic meter, the B+W caused a 970 K drop in temperature (more red). This was even more than I suspected, and I’d call it significantly un-neutral! More technically, we had a chart that equated this change w/ a +40 nm shift.

BTW, for comparison I also had a Nikon 2-stop and Tiffen 3-stop ND filter, and we measured these, too. The Nikon produced a 160 K rise in temperature (more blue). The Tiffen produced a 340 K rise (also more blue). These changes, of course, would not be as noticeable to the naked eye (if at all).

Then we measured some “correction” filters that might be a good match for the B+W.

The B+W’s 970 K drop suggested an 80d filter (which typically raises the temperature about 1300 K or so) would be a good place to start.

Below is Lee's approximation of what an 80d filter looks like:

207787

Glazers had a Lee resin 80d on hand, and the Sekonic said it actually added about 1,000 K.

And indeed, I've discovered the Lee 80d is a good "in the ballpark" correction for the B+W, good enough for enjoying finished slides on an overhead projector – while if I scan and go to PP, I do commonly add a touch of warmth.

[LabRat]

Yea Drew, the smokey amber light would be great for one of those surfing "endless summer" sunset photo shoots, and you wouldn't have to wait for sunset... ;-)

Just add longboards...

Steve K

[LabRat]

I don't believe that it is necessary to use a filter with color negative film as you "color correct" when printing. Back in '97 when comet Hale Boop was at its brightest I shot an eyepiece projection photo of the comet's very active nucleus on color negative film with a K1000 camera and had it processed and printed at one of those ubiquitous one hour photo labs. The resulting print was all an all green comet and didn't show the structure of the nucleus which was very dynamic in the eyepiece. This was before my film printing days and I showed the print to Dr. Fraknoi at Foothill college who, at the time, gave popular public lectures on astronomy. He couldn't (or wouldn't?) explain the color either. Now, of course, that should be an easy color correction in the enlarger. If you ever get the chance, do observe the nucleus of a comet through a high power eyepiece - I believe that I was using a 25mm eyepiece on 10" f10 telescope.

I shot that comet in B/W, but later found out the tail was 2 colors in green and blue...

I thought there was a defect in the Tri-X I shot as there was a couple of grain clumps/halation next to the nucleus, but I called the city astronomer, and he said they were excited the comet nucleus was breaking/shredding material, so guess what that "grain" was???

It took months of work to build an astro rig (while I was recovering from a serious flu illness), 2 weeks shooting under difficult conditions including heavy haze coming in right after 15 minute exposure started started, a wave of mosquitos, a heavy tripod metal breaking from fatigue, had to hand track with mount with one big knob, desert trips, another film defect involving loose lint on new 35mm film cassette, and more)... But ended up with ONE perfect frame!!!

A great amount of trouble, but that's why we do it...

Steve K

[Drew Wiley]

Tom - what I stated is absolutely correct. The proof is in the pudding - bowl after bowl of it. Please note that I made specific reference to Ektar, but it applies to a lesser degree to other color neg films too. Every serious Hollywood cinematographer knows it; otherwise, they wouldn't get the job. Unless the risk of crossover is corrected at the time of the shot via filtration, you cannot realistically post-correct it by any ordinary simple means. There are a few rather complicated cures involving intermediate tricolor separations.
Overlapping parts of separate dye curves create what I call "mud". That tendency is deliberately engineered into low contrast portrait films, which is exactly why they can't differentiate related hues well - everything similar wants to become a generic "pleasing skintone". Ektar was engineered to render cleaner colors overall more like chrome film instead, but suffers from cyan crossover.
All you can do with colorhead control is an overall balance adjustment, not un-mix mud once it's formed. Post-correcting in PS is not very realistic either. People who claim that they can do that have probably never seen a "clean" color print in their life; and theirs sure aren't.
Hale Bopp - wasn't that an early rock n' roll band, Halley and the Comets? I could barely make out the darn thing here. Up at my place in the Sierras one could see even the tail of it a third of the way across the sky with the naked eye. Once I saw the polar ice cap on Mars using just an ordinary pair of binoculars atop Sonora Pass. The serious astrophotog hobbyists haul big trailers up to the crest of the White Mtns around 11000 ft where the air is really clear. I've seen 16 inch reflector telescopes up there. Some of their mounts cost more than the truck that hauled it there.