Has anyone experienced with dollar store night lamp, preferably red one with black and white photo paper?
I don't have a safelight and I work in complete darkness. I am wondering experiences others have with it. I understand that it depends on light frequency, and with dollar store night lamp, we may not know what frequency range it emits. But I would still like to find if some people have experienced with that.
Te test proposed by @bvy is a nice one.
I would just add a couple of tips.
Photographic paper reacts to the blue component of white light. The amber light needs to have a very thick layer of filter, so use red that blocks more the green-blue components.
A visual test before you make the actual photographic test.
With only your safe light on (with your layers of cellophane paper), try to see some magazines with a clear green and blue bright colors over black. If you can not see the green and blue at all, you are probably safe.
You can also take a photo with a digital camera and watch the RGB histogram. It should show only red component. A tiny little green is acceptable.
Some images as a reference. Taken with a DLSR. (I tried using a phone but it is useless. The image is totally overexposed, no white balance... So it renders the lights white)
Red safelight. Settings: Iso 100, 1/200, f5.6 White balance>Sunlight.
Amber safelight. Settings: Iso 100, 1/200, f5.6 White balance>Sunlight.
Red cellophane paper (4 layers) over a small white led light. Settings: Iso 100, 1/200, f5.6 White balance>Sunlight.
Red cellophane paper over my lens (4 layers) pointing to an incandescent 60w bulb. (It is hot and too bright, so do not use it It is only a test to see the RGB channels) Settings: Iso 100, 1/2000, f5.6 White balance>Sunlight. I did not focus on this to blur the filament.
All have on this photos a bit of blue on the far left, but it is negible.
The histogram I am posting is a bit tricky because I did some not controlled tests. It is just a reference, but you can simply open the images on Photoshop and take a look at the channels, specially Blue and Green ones, and see that they have almost no component there.
It's likely to fog your paper. You need a specially designed red or amber filter or bulb. But... there's an easy test. Place a large coin on a sheet of unexposed photo paper. Expose the paper to your safelight for, say, twice the amount of time you expect the paper to be typically exposed to the safelight. The safelight should be in its intended location. Develop and fix the paper normally. If you see any outline of the coin, then your paper is being fogged by the safelight.
Dedicated safelight is the best. But when unavailable you can work with red bicycle light or red LED Christmas tree decoration.
Colored LEDs have a narrow emitting band and are usually safer than colored regular bulbs. But beware - some have an invisible narrow blue band which will ruin your work
Always remember no safelight is truly safe and keep your paper exposure to it to necessary minimum.
And before doing critical work make a safelight test - place an object, such as a key or a coin - in the middle of your paper for 5 minutes (or double your usual working time). Then develop it. If there is no silouhette your safelight is safe.
Photo print papers are mainly sensitive to violet and blue. Therefore, you can use a strong red filtered light bulb. The red coloration renders the outputted light void of violet and blue. The safelight started out red but it was soon discovered that a yellow lamp works also. This is because a yellow filter is also a blue blocker. As photo print papers evolved, some emulsions were treated to respond to green light. These are safe under a dimmer amber colored safelight. Films evolved also. A modern film is likely sensitive to all colors. Film development is best preformed in total darkness. However, modern films are least sensitive to green. Some can tolerate a dim green lamp for a minute or so.
Go ahead and purchase an inexpensive red lamp and try it with your brand of photo paper. It’s easy to run a test. In total darkness lay out a sheet of your photo paper on the actual work space you will be handling the paper, emulsion side up. Now lay six coins scattered on the paper. Turn on the safe light and wait one minute, and then pull a coin. Repeat every minute taking away a coin. After seven minutes of exposure to the red lamp, develop as usual. If the safelight is safe you will not see any trace of the outline of the coin after the paper is developed. Note: No safelight is perfectly safe; all fog paper after an extended exposure. It’s just a matter of how long the paper is allowed to remain exposed to the light rays from the lamp
For a similar price, you can buy a red LED bulb and replace an existing bulb with that. Run the tests as described in other posts, but you won't be messing around with cellophane or bike lights. Some newer RED leds are actually blue with a phosphor, instead you want the older style which will be a pure red.
This works for me developing UV sensitive films for etching, you'd need to check for photo film which is much more sensitive.
When testing the safelight it is not enough that white paper does not show any change. Safelight fogging could also lower image contrast. This is called pre-flashing the paper (when done intentionally).
A better test:
If you can see parts of the scissors on the image, you can count the strips to see how long safelight exposure is still safe.
