RA 4 Reversal Filtration

[@douwekrooshof881]

This is the first time I see a systematic explanation of the colour filtration, thank you for making it easier for us all to attempt this ourselves!

[@TheNakedPhotographer]

You're very welcome!

[@josephasghar]

You’re one of the very few darkroom technicians on KZbin using method. Thank you for that. Very interesting!

[@TheNakedPhotographer]

Glad it was helpful!

[@electroncraz91]

I did this 10 years ago with a homemade box camera and microcontroller with shutter and color wheel, RA-4 is heavily tungsten balanced, where red is iso 5, green iso 8-10, and blue iso100. Dual shutter for open/close, and color wheel with 3 of the gel filters and 1 naked. The color wheel auto exposed all 4 color channels with very consistent result in daylight! I had access to alot of fujicolor crystal archive II. Good stuff!

[@polyarthus4282]

do you have photos of it and your results lying somewhere on a website maybe? Sounds very interesting !

[@Amaraldo]

Great Job. Love the scientific approach to your videos. There's a prevailing false dichotomy that one is either scientific or artistic, but I find that having a good technical foundation is what truly frees your creativity.

[@hackaninstant]

To clarify the rinsed paper experiments, I was using Fuji CA paper with a 4200K light source (M3 flashbulb) and Y30 M20 filtration at ISO 10. Other tests using a 3200K light source with no filtration shot at ISO 12 yielded close colour balanced results. Outdoor tests in sunlight (5400K) with an 85b, Y50, and M30 at ISO 4 or so were OK. A filtration chart or graph detailing filtration vs colour temperature would be a big asset, along with a reliable way of reading colour temperature values whether rinsing paper or not.

[@TheNakedPhotographer]

I used a Sekonic C-500 color temperature meter to read my lighting. Daylight was 5500K and indoors was 3200K

[@burntoutelectronics]

1:22 I assume this development process is inspired from what I've seen from Ron Mowrey's (PE on photrio) old work from easily 20 years ago

[@The78bluedevils]

in the photo lab I worked in. we tested the head with a neutral gray background. number the corners. processed the print and evaluated the over all color balance. placed all 4 bulbs from the enlarger on a light box. looked for a color shift from the bulb itself. try to balance all the bulbs so they had the same color cast. retested to see how neutral all the corners were. this might be a luxury beyond most users, having a case of bulbs. this basically applies to color heads with 4 bulbs. number of jobs of negatives/prints varied daily. it helped having not to reprint an image over for a shift in color.

[@arturors30]

Wow, you know how to do these things. The results are pretty good. Congrats.

[@TheNakedPhotographer]

Thank you very much!

[@Jacksymmar]

Thanks for your sharing in the video. I myself used the similar reversal printing process to get prints from colour positive films in the darkroom. I also know someone out there shooting portraits on 16x20” colour negative papers in studio and get very good control of colour correction, almost the same as real life colour.

[@TheWayneStevenson]

Great work. I was playing around with reversal a little over a decade ago and life has been way too busy for me to get back into it, but I'm hoping to this year. Seen a lot of people doing it lately and that's so awesome to see. You can decrease the stack size a bit by using an unexposed 4x5 sheet of C-41. RA-4 is designed with that C-41 orange base layer in mind.

[@labo]

This is awesome!! I saw the videos of the guy who pre-rinse but I had doubts about that working... Now I'm sure, I don't think they're telling the whole story. Thank you for this video.

[@TheNakedPhotographer]

Without more information I can only guess that maybe they got lucky and are trying to find an explanation for why

[@guillermoperezsantos]

You can also use slides in the enlarger to make a positive ;)

[@GregoryVeizades]

Oh..... Ive not considered that!

[@ryang112]

Thank you for explaining this so well. I feel like I have a much better understanding of this process. Now I think I can do this!

[@shanematuszek9009]

Thanks!

[@afish7984]

You’re the real hero my friend.

[@pd1jdw630]

Wished cibachrome ore ilfochrome was still in production.

[@BobOgden1]

It'd be interesting to see how a strobe goes to get the exposure time down and make some portraits, the colours you got were lush in the end print of you

[@TheNakedPhotographer]

I’ve heard it can take 9600w/s or more!

[@BobOgden1]

@@TheNakedPhotographer - insert picture of blackened face with blown back hair 🤣

[@TrashTheLens]

Superb explanation. I really like how you describe your thought process.

[@TheNakedPhotographer]

Thank you kindly!

[@brineb58]

Fantastic video!!! Real simple yet full of info!!!

[@AdrianBacon]

Pretty cool video. In the studio, you could probably shoot with strobes and put the filter pack on the light(s) instead over the camera lens, then if you need to, pop it multiple times. That might be an interesting experiment.

[@felixzer1]

About the studio photo having a green/cyan cast: I have observed something similar when replacing the tungsten bulb in my enlarger by a LED bulb with a tungsten color balance. I expected filtration to stay more or less the same, but I actually ended up with a strong green cast. I think I have an explanation. I was using Fuji Crystal Archive and looking at the datasheet it seems that it has very narrow spectral sensitivity curves (and different form human eye cone sensitivity). LED lights, even when balances for a given color temperature can still have a irregular spectrum with extra peaks and low sensitivity areas. Depending of the exact LED model and paper type, it will cause a color cast.

[@TheNakedPhotographer]

I agree, it’s definitely the light, but without testing a tungsten light against it’s hard to know if it’s specific to led or not.

[@TShearPhoto]

I'd bet any light source will vary, possibly even between brands and models​. They all look different on a spectral curve even balanced at the same K value @@TheNakedPhotographer

[@rahandulcaspatal5276]

Muy bien me gustaría probar para usarlo en mi cámara mi idea es exterior lud de día entre las 11h y las 15h .crees que podría usar exclusivamente un solo filtro sobre la cámara .uno solo

[@tim31415]

Very interesting. Good info.

[@Sam_filmgeek]

Hey would pre-flashing the paper with a colour enlarger also be a method to not have to use all the filters?

[@MaximilianoOrtellideBarros]

Hi! Many thanks for your work! Can I ask for any recomendation about gelatine colour filters for buy? Many Many thanks in advance.

[@markosahlman9290]

What a great video! Thank you! So what (brand etc) are the filters you were using and where to get those?

[@TheNakedPhotographer]

I use Kodak gel filters for this video

[@bernardpanier8231]

Well done and clear approach. Thanks Question I have is: which color chemicals did you use (Tetenal, Bellini, other)? I do a rinse before the B/W (Ilford) developer to get rid of the blue dye. And, how would you approach pre-flashing the paper without a color enlarger?

[@iNerdier]

I would be interested in seeing this repeated with a tungsten constant light source. Having done quite a lot of research lately into the emissivity of led phosphors I’m willing to bet your light source is very uneven in output wavelengths. For all their flaws tungsten bulbs are at least consistent. Your filtration stacks up against the published material on ra-4 paper and the curve it’s trying to match though you might also want to try a low wavelength UV cutoff filter as well on sunny day (not the glass ones for lenses, they’re no good for 350-400nm) and see if that has any impact outdoors as the paper has some uv sensitivity that might throw things off. I think they came in cibachrome type filter kits. As regards contrast and paper speed, have you considered a pre-flash to help with both of those issues?

[@hankroarkphoto]

This is very cool. Thanks for sharing!

[@migueld2456]

Do you recommend a book to learn about color printing (not just b&w)? I really don't understand color:) thanks for your videos!

[@11anfilm96]

Interesting, I'm curious if you use RGB lights, to be able to reduce the number of filters, or maybe all filters.

[@PHONYJOSEPH]

You rule

[@TheNakedPhotographer]

Thanks!

[@szabodaniel9447]

Amazing accuracy and colour rendition, congratulations! I guess this could work for prints from slides, right?

[@Taka.1011]

It should work with prints from slides. In fact, it should be easier because you have the enlarger filtration to tune the colors, so I think you just need a heavy (but not totally) red filter for the enlarger lens, and from there, just correct wb/ add the necessary missing red by judging the print and adjusting the enlarger, just like a normal print

[@markorantanen]

How long do you keep paper in a black and white developer? And what temperature is the color developer? Have you noticed the effect of the temperature of the color developer on filtering?

[@TheNakedPhotographer]

I do every step for two minutes (except stop bath) at room temperature.

[@jsfotografie]

Amazing video :) will give it a try thx a ton :) cheers janosch

[@petehalupka1]

Hey thanks so much for this. Do you see a decrease in image quality? Does it oscillate between lower quality at the edges, and sharp in the middle? Thanks for any input. (Of course it isn't sheet film... but looking to feel out the quality)

[@TheNakedPhotographer]

Any variation in sharpness would be from the lens, not the process itself.

[@zazarowe]

I'm struggling with Kodak Endura I get really strong blue casts and it's driving me nuts.

[@zazarowe]

But your video is definitely helped me get my best results yet so thank you

[@DawidKadaj-sq2dm]

Could you make a video about making prints from slides using this process? I tried printing from Provia 100 on to Fuji crystal archive and got a massive contrast .

[@TheNakedPhotographer]

I intend to try it out, but I will have to shoot some slides first! One thought I’ve had is to do the first developer with Selectol-Soft or equivalent to see if that helps the contrast issue.

[@gountberlin1669]

great explanation! thx mate :)

[@igilump4045]

Where do I get such filters?

[@HugoPlaVentas]

Great video!! Did you experienced the weird texture appearing during the b&w negative maskimg phase?

[@TheNakedPhotographer]

I didn’t get any weird texture

[@HugoPlaVentas]

@@TheNakedPhotographer did you used Fuji Crystal Archive or kodak's?

[@TheNakedPhotographer]

I’ve used both. The final scene filtration will be a little different, but the methodology and final result will be the same. I’ve heard of some people getting a mottling in the blacks with Fuji when printing, but I’ve never experienced it in my prints

[@rahandulcaspatal5276]

Muy bien me parece un análisis del filtraje muy preciso y muy profesional. Por favor podría pedirte. Sé que es un esfuerzo pero. Podrías poner una fotografía sobre una mesa de del lote de filtros resultante ?. Lo digo por yo poder utilizar el más parecido posible de los que yo dispongo kzbin.info/www/bejne/fqezc5ylird8r5Ifeature=shared

[@MaximilianoOrtellideBarros]

Hi! Many thanks for your work! Can I ask for any recomendation about gelatine colour filters for buy? Many Many thanks in advance.

[@TheNakedPhotographer]

I use Kodak gels, the combination is explained in the video