Which light table app?? OR must be an LED

[splaaash]

I want to copy my negatives mostly B&W with my NEX 6 nikon tubes and 55mm micro nikkor macro lens😉

Works very well.I have an LED flat panel in my RV when i tried that i got even white light and a good copy.The LED is fixed on the ceiling,i dont want to remove it.

Then i downloaded white screen by m.maier, next bright screen light by lisekodroid lastly bright white screen by nathan bryant

I installed them no my samsung note then LG G pad & my LG G3

Firstly i photographed each screen with my NEX 6 & micro nikkor ALL the screens had very uneven illumination and at 200asa 160th sec @ f3.5 first image

But the screens show pink dotted lines and the tablet has very uneven lighting and very noticeable pink dotted lines

My LG G3 provided 250th sec at f3.5 produced at matrix of mostly dark pink squares????Very very small and tightly packed but not white
Although the LG G3 "looked" brightest the image looked grey

Is it possible to use a phone or tablet if so which app😎

 

[sevo]

Possible? Yes. But the quality will be poor - a computer monitor is rasterized, and no substitute for a proper light table. And no app can do anything about that - if any, you might stack opaque acrylic on top of the tablet, but with enough acrylic sheets on top, any light source would do just as well or even better...

 

[Dwig]

The only way to get acceptable results with monitor panels is to keep them far from the negative/slide so that they are way way out of focus. This will reduce the issues with both the overall (un)evenness of intensity and with the RGB matrix pattern.

 

[wkkato]

If you are getting discrete pixels or patters, then the screen is in at least partial focus, which you don't want. Move the screen farther away or put some frosted material over it. Also the LCD screens or LED screens are refreshed at some rate close to the shutter speeds you are using. This probably caused the uneven illumination that you experienced.

 

[Godfrey]

With the iPad mini, I've used a simple app named Flashlight that works ok, but it's not really even enough for critical work, nor it is color-temperature consistent. Better to get yourself a dedicated flat-panel lightbox like this one:

http://www.bhphotovideo.com/c/product/1003402-REG/gepe_802103_6x8_led_slim_lite.html

G

 

[splaaash]

I thought i read that a tablet / laptop were ok

I also read that a light box has been used,when i looked on line i found amazing price differences for the exact same light box

Then my microsoft laptop crashed and i lost ALL my data including my asus cloud back up which when i ask for a new pass tells me my email is wrong---while sending me email😡

Im going to look again for a light box in Europe

Pity about the phone /tablet would have been a great mobile solution😉

 

[Dwig]

I thought i read that a tablet / laptop were ok ...

They can be OK, by moderate quality standards, for use with color originals, but not likely "excellent".

For B&W, the light source color is not an issue. The only issue is evenness, which will generally be adequate if the LCD/LED panel is kept a decent distance away from the neg so that it is way out of focus and quite diffuse.

 

[Godfrey]

I thought i read that a tablet / laptop were ok
...

Flashlight on the iPad mini does ok for quickie stuff with B&W, but what's "ok" is a matter of opinion and what you're looking for. It's not good enough for my uses, other than when I'm in a hurry and just need to quickly see what the neg looks like.

If you already know the answer to your question, why ask it?

G

 

[splaaash]

I dont know the answer hence the question

often there will be an app not found by me thats ideal,therefore before i look for a lightbox im asking after all as i said a tablet would be ideal--even a phone perhaps a phone would be the best size wise

 

[Godfrey]

I dont know the answer hence the question

often there will be an app not found by me thats ideal,therefore before i look for a lightbox im asking after all as i said a tablet would be ideal--even a phone perhaps a phone would be the best size wise

Well, give Flashlight on the iPad a try, if you have an iPad. I'd find trying to use a phone as lightbox too restrictive.

G

 

[ColSebastianMoran]

Have to diffuse the screen or get it well out of focus.

Look closely at your tablet or phone screen at 1:1 and you'll see the problem, screen shows a pattern of dots. And, you can get really wicked moire patterns (spacing of dots on screen vs spacing of pixels on sensor) like this:

 

[willie_901]

What counts for this application is the light source's color rendering index (CRI).

If the light frequencies are discontinuous or inhomogeneous, accurate color rendition and even optimum B&W tonality are not possible.

LED lighting with a CRI of 90 (100 = perfect light content and distribution) is available. Most incandescent lamps have a CRI of 95. The best CRI with specialized fluorescent lamps is in the mid 80s, but a cool white fluorescent lamp has a CRI in the low 60s. Others are worse.

 

[splaaash]

My light table is 3feet by 2feet and about 10 inches high gives great luminescence and i found it more than ten years ago in a junk shop but it weighs a lot and wont go in my RV

I had considered an enlarger i found in Budapest compact in a small case or even a small Omega stored in parts but a simple copy stand a Leica NEX6 extension tube 55mm micro Nikkor an enlarger negative carrier and a light source ....
As Sony is hopeless at NFC or wi-fi transfer by USB to tablet and press print to RV printer either canon jet with about 18 watts or Laser printer with about 400w but with 500w solar and 320amphr battery no problem at mid day

So what is the best light source??Perhaps an enlarger with tungsten enlarger bulb...but always in an RV on the road possible but not reliable, 200/300w i can manage day or night except when its 38/40c as it was yeasterday and last week when my compressor fridge runs to often needing 45w then more than 150w for several minuets can be challenging

 

[sevo]

The best CRI with specialized fluorescent lamps is in the mid 80s

There used to be (and in some sizes there still are) dedicated light table fluorescent tubes with CRI ratings in the 94-96 range. Far from cheap, and only available from light table makers or prepress suppliers. They are probably not made any more and headed for extinction, as the demand from E6 labs and the prepress industry has dwindled.

 

[DrTebi]

What counts for this application is the light source's color rendering index (CRI).

If the light frequencies are discontinuous or inhomogeneous, accurate color rendition and even optimum B&W tonality are not possible.

LED lighting with a CRI of 90 (100 = perfect light content and distribution) is available. Most incandescent lamps have a CRI of 95. The best CRI with specialized fluorescent lamps is in the mid 80s, but a cool white fluorescent lamp has a CRI in the low 60s. Others are worse.

I agree. The CRI is important, especially when you want to do anything in color.

I have almost finished my DSLR scanning project, and I am using a Solux Halogen light bulb. It's a bit on the warm side, but that is easy to adjust with white balance. Much easier than spikes in a color distribution spectrum like that of a fluorescent light source or an LED.

For diffusers, I recommend to get a few samples from here:
http://www.acrylite-shop.com/US/us/acrylite-satinice/optimum-light-diffusion-addajh9ktfj.html

Sample pieces are only $3, and they are big enough for medium format, too.

If you find that the illumination is uneven, you can also have software calculate it out for you later. To do so, you need to take an image of your light source alone, and layer that over the negative/positive, and put the light source layer into "divide". Adjust the levels of the light source image if any values should be blown out. It works really well, once you figure it all out.

 

[splaaash]

Ill try that

I had never heard of CRI😕 In the past i used my light table to look at my negatives.I bought it as had wanted one and it was very inexpensive,now i will take it out from under a sofa😱 where i kept it and treat it with a lot more respect
I found it shortly after i had moved and no longer had a darkroom,as i was using a digital camera

For the RV ill buy a piece of plexi and a bulb try for a portable light table

Im learning

 

[ColSebastianMoran]

For high CRI, an incandescent light source is hard to beat.