Suggested backlight sources for scanning film with DSLR

Hi @SmilinDreamer

I haven’t had a change yet to try the CS-Lite just yet, but I think this is generally good advise. With that said, based on past tests I’ve done on light color, I would recommend trying both the White Light mode and the Cool Light mode for color negatives… You may find you like the final colors better with one of these vs the other!


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This file is a white paper that shows and explains my setup in detail. I’ve posted it here before. My solution was cheap, precise enough, and works well. It uses a sheet of half-inch thick railroad board (an all-black foam core material), a Viltrox L-116t light, AC power supply, some Velcro, some scrap 1"x2" lumber, and the Essential Film Holder. Read on for photos and tips.

Good advice… As an ex-photo lab guy, I can report that no two film emulsions respond the same way when scanned or printed.

At the lab where I ran the scanning department back in 2000 to 2004, we had nine Kodak Bremson HR-500 scanners. They were networked to a Kodak DP-2 lab software database that was also Kodak’s scanner driver and rendering engine.

During our off-season, we would calibrate a “master scanner” to respond well to our primary film of choice, Kodak Portra 160NC. This involved creating “film terms” — a text file of values representing color corrections that amounted to “slope” corrections at various exposures from -2 to +2 stops of film exposure. Different exposures affect color balance differently, because the three light sensitive layers respond differently to light intensity. You get one color balance with underexposure, and another with overexposure.

Different film manufacturers use different shades of “orange masks” that are tailored to the particular chemistry of their emulsions. This means that the film terms we created for Portra 160NC did not work for Fujicolor or Kodacolor or any other negative film. We even had a different film term file for Portra 400VC, because of its higher saturation and vivid contrast. (Kodak no longer makes 160NC and 400VC versions of Portra. Those “normal contrast” and “vivid contrast” films were aimed at portrait photographers and sports team photographers, respectively. The newer films are basically similar to each other in contrast and saturation.)

What I’m getting at is that light source filtration and software interpretation both matter a LOT when digitizing film.

I scan B&W films at 4400K, because it uses all the LEDs on my Viltrox panel and provides maximum brightness.

I scan older, amateur slide films at 3300K, because they were designed for projection with 3350K ELH quartz halogen lamps. Older professional chrome films work better at 5000K, because they were often made to look best on a 5000K light box.

I scan color negatives at whatever temperature seems to give me a most pleasing result, and that varies from brand to brand, age to age, emulsion to emulsion. Most films work well at 3300K, as they would be printed on color enlargers or printers using 3200K quartz-halogen lamp sources with some small amount of yellow and magenta filtration.

Recently picked up a SmallRig P200 with a claimed 98+ CRI and my scanning has definitely improved since upgrading. I also use the foam insert that came with it to hold it in place and have the USB-C through the foam. I had the Viltoxlight L116T before and could not figure out how to make it stay flat. The small rig light also comes with (2) 1/4" adapters. All for $65 really affordable.

Thanks for posting this and welcome to the forum. It’s always good to see new light sources and this one looks very useful, only available in the US as far as I can see. Have you seen the post on here about 3D printing a base for the Vitrox 116T?

You’ve highlighted a problem when using the LED panels that are designed as video lights because the controls are often on the back and there is no real need for them to lie flat. Some panels are now being designed specifically as scanning lights so lie flat and the controls are accessible, such as the (much smaller) Cinestill CS-Lite.

The Smallrig P200 is rated as 98CRI so that is potentially very good (though not easy to verify). There are other 192 LED panels on the market which are rated as >95 CRI such as:

Ojelay SL-192AI
KingMa SL-192AI

These four look so similar that I can’t help but think that they are all referring to the same product, I may be wrong though.

Hi guys,
Can you please correct my setup if I doing something wrong
I used Galaxy S10+ and Iphone 8 as light sources, on max brightness using Canon 6D with Canon 50/2.8 Macro lens @5.6 and got ~1/6 at ISO100 ( I would like to have some wiggle room to be able to go up to f11 )
Is this what you guys getting with your smartphone/ipad setup ? Seems to be pretty low for my liking.
I prefer to have something like 1/80 just to make sure I wont have minimum pixel shift.
Of course I will be using IR remote
But still any vibration will show at this stutter speed :frowning:

Hi all,

I have some interesting findings regarding backlight sources that could be of use to some out here, so I wanted to share these to “give back” for the many things I learned on this forum, and also to get some inputs. I recently created a new table-top scanning setup for 35 mm, after some previous adventures with an up-side-down enlarger, since this was more convenient:

This enabled me to try multiple light sources: A Solux bulb in a metal mount (which gets rather hot), a recently acquired more convenient (cheap, compact, bright, and not getting hot) Rollei Lumen Square (~35 EUR), which can be controlled at various color temperatures through a phone app, and my iPad. Logic has it that the 99+ CRI daylight bulb should be better than a cheap LED panel, correct? So I did some tests that I wanted to share. The old Nikon PS-6 slide and negative holder has a glass diffuser mounted very close to the negative/slide but not touching it. This is as it standard comes.

Test procedure:

  1. Take (RAW) pics of glass diffuser in PS-6 without negative/slide with fixed aperture (f8)
  2. Decrease shutter speed until peaking occurs with Rawdigger (ETTR)
  3. Back-off 2/3 stop and use that picture in LR with NLP2.3 profile
  4. Use white balance picker in LR to see how “white” the light is
  5. Drop exposure to look for vignetting and color cast

Bare Solux bulb at distance as in pictures above
Rollei Lumen with it’s extra diffuser at about 20 mm from PS-6
iPad Pro 9.7" (2016) directly against PS-6
Bare Solux with extra opal glass diffuser (see pic above) about 5 cm from PS-6


Rawdigger histograms, left to right: Bare Solux, Rollei at 4100K, iPad, Solux + extra opal glass
(I do not know what the bottom G2 (2nd green channel) in Rawdigger represents)
Horizontal is EV, vertical is as far as I understand the amount of pixels with that EV level. Scales for all channels per light are the same.

I noticed that for the bare Solux bulb, the R, G, and B histograms did not have the same shape. This leads to color-casts in a scan since the R, G, and B channels do not overlap after whitepoint setting with the LR color picker:

(center = white, but color shifts towards blue in the corners. The slight vignetting is most likely due to the lens, as I found out, since it’s also there and similar when the light evenness is varied.) The non-equal histograms for the various channels in the Rawdigger plot cause the color cast. Eventually I traced this down to the Solux requiring more diffusion (see below).

The cheap Rollei has impressively similar histograms for R, G, and B, and this provides nice overlap in LR after a color picker WB in the center:

This white light should give accurate colors, correct?

The iPad has sharper histograms, which would translate in “better color separation” and seems more “ideal” after reading in various places here about proper RGB light sources(?), but is less bright and takes 3 seconds shutter speed per shot (without film). The consistent shape of the histograms results in good overlap and no color casts in LR:

(blue in extreme corners is peaking of black)

I was puzzled about the blue color casts of the Solux towards the corners so I placed an additional opal diffuser in between the Solux and the PS-6. This cleaned up the RAW histogram and made the individual channels similar in shape (right pic in the Rawdigger plot above), and resulted also in removing most of the color cast in LR:

The individual histograms still do not overlap as good as for the Rollei though.

Lessons learned from this exercise:

  1. Rollei impresses and is convenient and bright, as well as enables different color temperatures which some claim is better for slides vs. B&W vs. negatives.
  2. Solux takes some doing to get homogeneous and neutral but is continuous spectrum with CRI99+. Opinions seem to vary as what is best: High CRI continuous, or well defined and separated RGB. With the Rollei, and my lens, sensor, and other in-betweens, I obtain smooth neutral grey across the entire area, so I should get neutral colors as well (no?), provided I do the same ritual with the Rollei on an unexposed section of film?
  3. iPad impresses but its light is too weak for my setup.

Overall, I conclude that the Rollei will do just fine and the Solux is not worth the hassle of working with an extremely hot light and less convenient setup, although I still worry that LED’s are not continuous spectrum (but neither is my camera’s sensor).




Bayer filter sensors have two photon collectors filtered for green and one each for red and blue. RawDigger can be set to display the two green channels separately (default setting) or not.

Thanks. Never realized that. Clear. I could have summed the greens. Still, from the above, one can use Rawdigger to check for homogeneity of the light, which was new to me. It could also explain why some folks here see funky color variations in their scans.

Which leaves me wondering: Is my conclusion correct that I might as well use the Rollei and would not have to use the available, but less convenient, Solux?

Is this correct: For scanning, I would simply ETTR with Rawdigger this way on a non-exposed section of a negative strip, and use the LR eyedropper on a non-clipping frame from that, to determine exposure as well as WB for the film and use those settings for the entire film?

Can’t say anything about this. I have seen neither of the two lights and respective results.

You best consult the GUIDE you can access through the link in the black header of the page (scroll up to find the link)

In general, exposing to the right provides a good starting point for the conversion. About exposure, the guide recommends the following:

Keep the SAME exposure for the entire roll. This will cut down on variance during processing. Beware auto exposure, as the small settings changes throughout the roll will create unwanted variance.

While this recommendation might make sense if you fill rolls with one scene, it might not be optimal for film strips that cover many different objects and densities due to variations in exposure of the film. Whether a roll is evenly used (same object and exposure) or not could make a difference and I usually test different camera settings in unevenly exposed rolls.

I also understand NLP’s initial conversion as a starting point rather than as an end result…but we’re getting off topic here…

Do enlargers work well as a light source? I got a free colour Nikor 6x7 enlarger, which is super bright. Also, it has knobs which adjust the colour of the light source so I should be able to counteract the film bases orange colour cast. Also, the light coming out of it is already pretty diffused and I am using a EFH, which will further diffuse the light

The only things I am worried about is the CRI of the light, and it is kinda a warmer light (but I can counteract that with the enlarger’s built-in filters.

I was just curious if anyone has experience of using an enlarger as a light source and how it compares to using a LED light source?


I’ve worked with this and found that lighting was not even enough for medium format negatives and that the colour filters did not matter that much. After all, NLP will deal with colour fairly well in most cases.

Search the forum for more comments on enlargers. Also, check out other threads about light sources and setups, they cover lots of ideas and experience.

@Digitizer So I tried using the enlarger lamp and it actually worked really well. I don’t know if it is just the design of my enlarger lamp housing. But the light bounces 90 degrees into a box that has sides that are some sort of white foam before it shines out the bottom (where the film holder would go) through some sort of white diffuser. Then through the EFH’s diffuser so the light seems pretty good.

Sadly, I was only able to scan two frames because the old bulb blew out. It is really easy though to get replacements. Once I fix it, I’ll experiment more and post the results. I will likely get an LED panel though since the enlarger head is quite awkward and it gets pretty hot. Though I can fix that by rigging up a computer fan to cool the bulb.

Does anyone have experience/tested the Cinestill CS-Lite?
It has a 95 CRI and the reported specs seem comparable to the Viltrox 116T that I’ve seen recommended as a budget-friendly light source.

It seems like a great entry-level scanning setup since there is a fitting 35mm film holder, but at 90$/80€ for the kit it seems almost too good to be true (considering the price for e.g. the essential film holder or Skier box), so I’m hesitant on pulling the trigger just to get a disappointing product.

Curious to hear your thoughts on it!

I have one and I can’t actually think of anything bad to say about it though I haven’t compared it with other panels personally. Just some detail about it in case it’s useful.

The CS-Lite is 175mm x 120mm x 20mm overall and the illuminated area is 149mm x 94mm, so just a bit too narrow to think of doing uncropped 5"x4" but fine if you are stitching across the short side if you get my meaning. The surface of the lit area has a pure white matt frosted appearance and on my setup I use it about 3 cms below the negative. It’s bright, I get about 1/160 sec at f8 at 200 iso. There is a little bit of illumination unevenness very close to the edges but otherwise it is very even. It’s rated as >95 CRI (Colour Rendering Index) which really should be fine, 99 CRI panels are super expensive as you will know. I believe that the highest CRI rating is for the warm setting. I’ve seen excellent results posted using the CS-Lite with NLP but I bought it for slides/transparencies mainly.

There is a 1/4" tripod thread at the centre of one of the long sides (useful perhaps for mounting on a table tripod, or even for using as a Macro light source). The captive USB lead is just under 2m long and the control switch is about 45 cms from the body on that lead. It needs a 1.6 Amp 5V USB ‘A’ power source for full brightness. Standard Iphone power plugs are 1A (5W) but Ipad power plugs like the A1357 or A1401 are 2 Amp (10W) and easily available for less that £10, I’m using an A1357. They say that 5W power plug means it will still work fine but it will be half as bright though I haven’t tested this.

Having the control switch on the lead works very well, much better for me than those other video lights that have them on the back for this application. It is also completely flat on the back so no 3D-printed holders required.

Mine came with a textured ‘collimator’ sheet but they now sell these separately in packs of 2 as the CS-LiteBrite+ and it is not included with the CS-Lite. There is also a useful mask to reduce the area for 35mm and I’d recommend making your own for medium format etc. to reduce extraneous spill light, as you would with any panel.

Basically I like it.

hello! informations that you give here is very useful, thank you for that. but i have one question for now. when using ipad, do you use any diffusion material like when you are using led panel? thank you

Billie, good question. For iPad and iPhone, I did not use a diffuser, just enough spacing so the pixels in the screen are way out of focus. The current iPad and iPhone displaying white gives a three-color-narrow-band spectrum that works well, perhaps a bit stylized, but is not very bright. Today I prefer for backlight: electronic flash (w/diffuser of course), any of the small video lights, or the CSLite.

Thank you so much for the answer; it’s really helpful. I have another question that just crossed my mind. What do you think about using the Godox LED P260C for scanning? As for the diffuser, I can’t use the recommended Dura-Lar because it’s so expensive here. On Amazon, it’s listed at $18, but in my country, it goes up to $80. I don’t think I can justify that price yet. What about using generic tracing paper instead? or is there any other recomendation for diffuser?

Oh, and one more thing. I’m curious about the electronic flash setup. Can you please provide a photo of the setup or some kind of reference on how an electronic flash can be set up for scanning?