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Ra4 safelight

pentaxuser

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mshchem said:
I've used Thomas sodium lights with the color filters. It's on the other side of the room, I don't have paper out for more than a couple minutes. There's just no truly safe light.
Click to expand...

It sounds from the above statement as if the Thomas sodium lights were/are OK and for as long as at least two minutes but I am unsure whether this was for the older slower papers only

If you can clarify this for me I'd be grateful

Thanks

pentaxuser
 

Don_ih

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Markpot said:
What do you think about buying a smart-home-led-lamp that you can connect with the phone and then set your own wavelenght of 589nm and set the brightness very low.
Click to expand...

I doubt you could set the brightness of any such bulb low enough.
 

pentaxuser

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The problem is that it has been stated that 589 nm is unsafe for any of the papers you can buy now so it would seem that there isn't a "right" wavelength that's safe What seems to be the unknown is whether there is an illumination level that is low enough to allow you to both see what you are doing and is long enough to allow you to do what you need

Testing may be the only way to establish this. What may be crucial is how you will then process the RA4 paper. If it is open trays then you will need longer than will be the case if you can put the paper into a lightproof drum. In that case a few seconds to remove the paper from its box and place into the easel may be OK

The Wotan DUKA safelights emitting 589 are as koraks has said 1980s and 1990s technology In the era of modern "digital RA4 paper there has been another maker called Heiland that appears to claim it has a dimmed yellow safelight that at 590nm is safe for processing colour paper. It uses LEDs but that's all I can find so we are back to the question of "safe" for how long

I imagine that Heiland has tested it with current RA4 paper to be able to claim it is safe but in the contents of what I have found I cannot see any details

I recall seeing a video on the combined b&w and colour safe light but cannot recall what was said. It might be worthwhile trying to find the Heiland video and if the answer isn't there then I would write to Heiland and ask specific questions

Best of luck


pentaxuser
 

mshchem

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Current cut Fuji CA paper.
 

koraks

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Markpot said:
What do you think about buying a smart-home-led-lamp that you can connect with the phone and then set your own wavelenght of 589nm and set the brightness very low. Does this maybe work?
Click to expand...

No, this will not work. You cannot set the wavelength of those lights to 589nm. These lights contain usually three LEDs at 460, 525 and 620nm. The colors are made by varying the intensity of these three LEDs. Orange would be made by mixing green and red. Both this green and red will fog the paper.
There may be types with an addition white LED which of course also doesn't help.

What you can do is try to find or build a fixture with 590nm LEDs and then reduce its intensity to the bare minimum you need to see anything. This will get you maybe a few seconds of "safe"light and color shifts and fogging if you expose the paper too long, ad indicated before

Total darkness is a safe bet and not as difficult or cumbersome as you may fear once you get used to it.

If you really want to be able to see, get a pair of IR goggles.
 

mshchem

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Low pressure Sodium vapor lamps are great for B&W, humans see this wavelength very easily. B&W not so much.

For color work, I have found that waiting the 20 minutes for your eyesight to get fully adjusted you can see fine with a single Thomas safelight, with the FCD filters in place, at least 10 feet away, no more than a couple of minutes.

It's just a matter of time and distance. At these extremely low illumination levels I can get away with it.

I use the safelight when I'm using my old Kodak processors, NOT, with tubes or roller transport machines.

RA4 paper sees all visible light.
 

mshchem

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Fatih Ayoglu

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If you cannot work in total darkness, my recommendation would be IR Google’s. I have one and use it for RA4 print and BW films masking for C41 films. No issues so far
 

DREW WILEY

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No color shift at that point, Koraks. The Minilux is a tiny device. But that 12 sec was just for testing purposes. I don't think I've ever turned it on for serious use more than 3 or 4 seconds when potentially having difficulty locating the loading roller cones on the big roll cutting machine, or something else tricky like that. I otherwise work in total darkness.
 

pentaxuser

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mshchem said:
Current cut Fuji CA paper.
Click to expand...

Thanks so 2 mins at the level which you mention without seeing any shift to cyan. All that's required is enough light to basically see your way around the working area in the darkroom

pentaxuser
 

pentaxuser

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Fatih Ayoglu said:
If you cannot work in total darkness, my recommendation would be IR Google’s. I have one and use it for RA4 print and BW films masking for C41 films. No issues so far
Click to expand...

Interesting. What's the light source on a pair of these goggles? I take it there is some kind of light source built into the googles

Thanks

pentaxuser
 

DREW WILEY

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IR = infrared. That's the kind of light the googles use. They output it themselves.
 

pentaxuser

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koraks said:
Not long. I've tested 590nm LED quite extensively. It's a marginal situation at best and I don't recommend it.
Click to expand...

I wonder why Heiland would sell a combined b&w and colour safelight for what seems to be a lot of money unless it was sure it worked. Yes if it works for a few seconds only before cyan shifts appear on the prints then strictly speaking saying it works is true but I'd have thought that as short a time as you suggest hardly qualifies as working

If it were me I'd want to ask some direct questions in writing of Mr Heiland himself to see what he says


pentaxuser
 

DREW WILEY

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Heiland is allegedly "sure it works" for what specifically? You can't just make the assumption that everything is the same, or that a known color paper won't be subsequently tweaked in a manner different from how it started out. That is why the only common denominator advice Fuji spells out on their spec sheet is "total darkness". Anything otherwise ya gotta test for.

And there have been all kinds of very expensive darkroom devices that never did work all that well to begin with. Some were too fancy for their own good. Others simply didn't have a track record. I don't take anything for granted. And I specialized in selling high-end equipment (non-photographic) for the last 15 years before I retired. You'd be amazed at the number of variables that DON'T getting taken into account when prototyping a device. And I'm talking industrial manufacturers vastly bigger than Heliand, and routine daily purchases far more expensive than anything they make.
Just developing a valid track record takes a long time.
 

pentaxuser

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koraks said:
IR LEDs.



LOL. Right.
Click to expand...

Thanks for both answers and to others for the first answer. As far as the second is concerned I was simply giving what I thought to be a reasonable conclusion from mshchem's replies Maybe you are laughing at his answer in the sense that anyone stating what he appears to have stated about 2 mins with a Thomas safelight illumination deserves a laugh.

What I think we may be sure of is that what he sees as OK prints after 2 mins of safelight exposure are OK to him. I have never seen any of his prints that I can recall or if I have I certainly don't recall a cyan shift but as we know I failed to see any colour crossover in a negative sent I think to you by David Lyga but you did

Can I ask: Have you seen any of mshchem's prints in order to make a judgement?

pentaxuser
 

koraks

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@pentaxuser I think @mshchem said something about "a couple of minutes", but it was you who made that into "exactly two minutes" and tried to cast it into concrete in other ways as well. For all we know he actually meant something along the lines of "a reasonable amount of time that almost feels like a few minutes", but that in reality turns out to be much less. I understand it's sometimes hard to not take things literally, but that's how it works.

I'm laughing at the suggestion that you could leave Fuji paper out under a visible safelight for 2 minutes and not get cyan crossover at least in the highlights. No way, no in this universe. But hey, if anyone wants to believe otherwise, go ahead, knock yourself out.
 

Fatih Ayoglu

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pentaxuser said:
Interesting. What's the light source on a pair of these goggles? I take it there is some kind of light source built into the googles

Thanks

pentaxuser
Click to expand...

pentaxuser said:
Interesting. What's the light source on a pair of these goggles? I take it there is some kind of light source built into the googles

Thanks

pentaxuser
Click to expand...

I also put some old film pieces to cut the IR light. So far so good
 

mshchem

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Laughing justified.

I don't think that the emulsion side of my Fuji CA paper was exposed for more than 15 seconds and that's from several feet away.
I would expose the paper, step 2 feet lay the paper face down in a tray of warm water, then I would apply the print to the processor, 45 seconds developer, 45 seconds blix.
One of these machines. 60 year time machine.


If you're interested in color printing, get used to working in the dark, otherwise you will be chasing your tail.
 

BMbikerider

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Is printing RA4 colour when using a DUKA safelight actually safe? Well in my view it is perfectly safe.

In view of some of the the comments on the subject in this thread I decided to do a series of tests just to prove what could be misguided information in what has been stated or or has been found. printing RA4 is no more more difficult than B&W (Not of course accounting for the more exact temperatures and times needed.) I have been printing RA4 since around 1992 starting with Kodak materials and chemicals, but with the demise of Kodak items I have been forced to fall back onto using Fuji paper and chemicals. I will be quite honest I don't particularly like Fuji RA4, but you have to work with what you can get hold of.

In the test that I carried out I used cut sheets of Fuji Crystal Archive glossy paper and Fuji CPRA developer and Blix with an acetic acid stop bath in between. The print of the thistles and the bee, I made was on the same paper/developer combination but the negative film was Kodak Gold 200. The lighting on that day was bright but with few shadows.

My darkroom is quite a modest size being approx 2.75m long and about 2.00m broad. The walls are a very pale cream and the ceiling is white. Both are matt painted. The reason I included this information was for you to judge the size of room that a DUKA can illuminate and still not fog the paper. The lamp itself sits on a windowsill next to a backed out window. (white blackout material) The lamp is angled at roughly 45 degrees towards the blackout material, so the light is reflected off that upwards towards the ceiling and is completely diffused. I also work between the lamp and the workbench, so no direct light can reach the light sensitive paper. Allowing for the width of my workbench, the lamp is about 1.25m behind me. I can see to work quite easily but not read small printed writing.

The lamp house is adjustable from 1 to 50 marked out 1, 5. 10, 30, and 50 sections. 1 being the dimmest setting and 50 being full illumination. I have the lamp adjusted with the marker at 2/3s of the segment between 5 and 10 (closer to 10) so it is still at quite a low level of brightness.

The bulb is the 2nd I have had, the original expired about 15-20 years ago. I understand the value of the light does change over time and becomes less effective, but I rarely have to change the filtration which I put down to different film stocks and or development anyway. The filtration to produce the print was 65M 75Y which is very close to my average and the exposure was 7.3 seconds. The print was developed for 45s @ 35 degrees +/- .2 of a degree. In this respect Fuji paper is far more stable than the Kodak equivalent was, with more constant filtration by Fuji

The 1st test strip was exposed to the room main light for 10 seconds. The 2nd test strip was totally unexposed paper. The 3rd test strip was exposed to the safelight only for 2 mins and that is to all intents and purposes the same as the unexposed strip, (No2 in the series). The 4th test strip was exposed to the safelight for 3.5 minutes and this when viewed in tungsten light or LED, as expected. does show a marked cyan cast.


The largest print I can make in the darkroom is 12x16 due to the size of my processor and the exposure time for that has never exceeded 50 seconds which allows me a large margin of safety if I prepare beforehand. No 3 and 4 test strips were placed on the workbench where I would normally work so any ambient sodium light would be at the same level as if I was printing normally.


So with over 32 years experience of using RA4 paper and a Duka Safelight, I personally think under normal usage, the two can work safely together. Unless I had been told on Photrio there had been a paper speed increase a few years back I would have been non the wiser. This is of course my personal finding and is not anecdotal.

As for using my Duka when printing B&W it is in the same location and the level of light output is always set on the maximum of 50 and never have I had an instance of fogging, even though size for size B&W paper is slower and so exposed to the light for longer times.

I suggest that without visible proof that can be seen by 3rd parties, simply quoting from tables or other sources that information about what can be done, or as the case may be, cannot be done, is possibly flawed and not always as others may find them. Giving out such formation can dissuade people from trying it out for them selves, and as I have done, learned from my personal experience over many years.

I do agree that the light levels in a darkroom when colour printing have to be very subdued but never the less a DUKA safelight is a viable option.
 

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koraks

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Your 2 minute strip shows some cyan fog, which puts the time before fogging of whites occurs at something a little less than 2 minutes.

However, the time to take for the whites to go cyan is NOT a safe time. While you were doing your testing, I happened to be doing mine.

Here's a step wedge under my safelight, which is evidently much less safe (by about 2.5 stops) than yours:

The accompanying text in the blog I linked above mentions that the 20 second wedge is the last one that shows no visible tone; the 30 second wedge shows a slight cyan discoloration, roughly similar to your 2 minute wedge.

I then did a test print with one half fogged to the 'safe' 20 seconds, and one half unfogged:

Note how the borders are white, although the left side of the sheet (including borders) was fogged for the same time to the safelight. The color shift in the image area, however, is dramatic.

This is a further test with the safelight fogging tuned down another two stops. In your darkroom conditions, and assuming that your 2 minute wedge was unfogged, this would be a 30 second exposure - in my darkroom it was a whole lot shorter - 5 seconds. But that is inconsequential; what matters is how it relates to the time we see fog appear to the whites.


In this sheet, I fogged the left band at 2 stops below the longest time that did not produce a cyan tone to the whites. As you can tell, the color cast is still significant.

To get rid of the color cast, I'd have to go back down at least about 2 stops more or so. Translating this to your darkroom, this would give you a safe time window of less than 7.5 seconds.

The reason why you're not seeing the problem is probably because you're filtering out the color cast, and you're being reasonably consistent in how much safelight fogging you expose your paper to. However, the result of your approach is that you're printing with a reduced gamut on the paper; you cannot by definition use the full range of hues of the paper if you contaminate it all with a hint of cyan.

You're of course free to do and believe as you will, but please understand that the simple fogging test that you have performed is by no means adequate for color work. It takes a fogging test with an image exposure (before or after it, or both, if you prefer) to verify that your safelight conditions are truly safe - or rather, for what period of time they are safe. You will find the actual safe time window is substantially shorter than you believe it is.
 

MattKing

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A fogging test will be inadequate if the only thing thing one looks for is visible fog in the image.
If safelight exposure changes the response of the paper to the exposed image, then the safelight is not "safe".
Changes can include changes in contrast, non-linear changes in colour response, and non-linear changes in overall sensitivity.
It also wasn't clear to me whether the test included both pre-exposure and post-exposure fogging.
 
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