The difference between the color capture method on different scanners

[Joshua Echevarria]

What is the difference between scanners with Sequential RGB+Infrared color capture method vs a bayer pattern color capture method?  

I see that laser graphics offers both models and that the arriscan has the Sequential RGB+Infrared.  What is gained from the rgb method ?

[Perry Paolantonio]

Sequential RGB uses a monochrome sensor to make the image. Three images are taken, each with a different color light - Red, Green, Blue. The three channels are combined into a color image. Doing it this way you can do 16 bits per channel, assuming the sensor in the camera is 16 bit. If you bring a color image into Photoshop and look at the R/G/B channel separately, they're represented as monochrome images. This is the same thing, but in reverse. 

The ScanStation uses a faster Bayer sensor, but with 2-flash HDR and oversampling, the results are in many cases pretty comparable to a sequential RGB scan, in terms of bit depth.

IR is only used to create a dirt map that some restoration software can use. In the case of the Director, DICE is built in, so it uses that to do some in-scan cleanup of dirty film. If we had a director, we probably wouldn't use it, because it's not very good and it's baking those "corrections" into the image. But you don't have to have the cleanup done in-scanner. You can just output the straight scan along with a dirt map. This is handy, if your restoration software supports it. The basic idea is that any dirt that's physically on the film will not allow the IR light to pass through. the dirt map is a black and white image, with spots representing the location of the dirt on that frame. It's a second scan made at the same time, to a separate folder. The restoration software (if it supports it) can load that IR map up, and only target fixes where the dirt is. 

Of course this all sounds great, but doesn't account for dirt that's baked into a print (say, something that was on the negative, then got printed into the film). In that case, it's part of the picture, not physical dirt on the film, so it won't show up on a dirt map. But it can really speed up cleanup on dirty prints because you're not processing the entire frame, just the spots where there's actually dirt. 

[Robert Houllahan]

Film scanning was R/G/B and sometimes IR from the very beginning.

Currently any "Big" film you see will have been scanned on a true RGB scanner like the Scannity or Arriscan both of which can produce 16bit per color channel scans. One of the really big differences with a true RGB scan vs. a CFA scanner is the color accuracy and separation of the color channels. This tends to make scans which have better detail especially in denser areas of the negative.

As for IR dirt map DICE it could have been a much more widely used and developed system in motion picture scanning. Kodak decided to charge incredible license fees for DICE in the past and that unfortunately kind of hurt the use of DICE. Subsequently not many post apps really fully developed more advanced tools built around the 2-bit dirtmap alpha channel available in DPX.

Edited January 6 by Robert Houllahan

[Joshua Echevarria]

On 1/6/2025 at 2:08 PM, Robert Houllahan said:

Film scanning was R/G/B and sometimes IR from the very beginning.

Currently any "Big" film you see will have been scanned on a true RGB scanner like the Scannity or Arriscan both of which can produce 16bit per color channel scans. One of the really big differences with a true RGB scan vs. a CFA scanner is the color accuracy and separation of the color channels. This tends to make scans which have better detail especially in denser areas of the negative.

As for IR dirt map DICE it could have been a much more widely used and developed system in motion picture scanning. Kodak decided to charge incredible license fees for DICE in the past and that unfortunately kind of hurt the use of DICE. Subsequently not many post apps really fully developed more advanced tools built around the 2-bit dirtmap alpha channel available in DPX.

Thanks for your reply Robert.  I posted the same question in another forum as well and based on the answers I've received, the different between and RGB scan from the Doctor, Arriscan etc and a 2 flash HDR from a Scan Station for example, is negligible.  Whats your take on that?

[Robert Houllahan]

4 minutes ago, Joshua Echevarria said:

Thanks for your reply Robert.  I posted the same question in another forum as well and based on the answers I've received, the different between and RGB scan from the Doctor, Arriscan etc and a 2 flash HDR from a Scan Station for example, is negligible.  Whats your take on that?

I am doing a selects scan for a S16mm feature right now that did extensive tests on multiple Scan Station 65K HDR scanners and went with the Arriscan because it is a better scan for freshly shot negative. The Arriscan out performs the Scan Station in terms of detail and color accuracy at the expense of being slower and slightly less stable overall.

The difference really depends allot on the final post pipeline and if the scan is for Web or TV or Theatrical.

Almost all small post shops only have a Scan Station the Director or Arriscan are not really too commonly available.

[Joshua Echevarria]

22 minutes ago, Robert Houllahan said:

I am doing a selects scan for a S16mm feature right now that did extensive tests on multiple Scan Station 65K HDR scanners and went with the Arriscan because it is a better scan for freshly shot negative. The Arriscan out performs the Scan Station in terms of detail and color accuracy at the expense of being slower and slightly less stable overall.

The difference really depends allot on the final post pipeline and if the scan is for Web or TV or Theatrical.

Almost all small post shops only have a Scan Station the Director or Arriscan are not really too commonly available.

I appreciate your insight.  

I'm up in the air right now.  Its for a short that is guaranteed a theatrical screening.  There is only 1 LG Director in NY that I know of.  Everyone else has a scanstation.    do you have any side by side comparisons?

[Robert Houllahan]

1 hour ago, Joshua Echevarria said:

I appreciate your insight.  

I'm up in the air right now.  Its for a short that is guaranteed a theatrical screening.  There is only 1 LG Director in NY that I know of.  Everyone else has a scanstation.    do you have any side by side comparisons?

I know Metro has an older 4K Director I am not sure how that compares to the current Scan Station you could probably talk to Jack at Metro about that.

New Directors use the 6.5K sensor but it is a monochrome one instead of color and has a piezo shift like the Arriscan to make 13.5K out of a 6.5K sensor. The older ones used a 4K monochrome CCD I am not sure how that performs but they did have 2-flash and 3-flash on them from the beginning.

As for comparisons you will have a hard time finding any and the film I am scanning now did allot of tests they spent the time effort and funds to compare the results for their film. I know Co3 NY has an Arriscan and Scannity but I do not think they take smaller jobs.

It really comes down to how much extra time and cost do you want to go to squeeze the very best out of the film and how much post finishing you plan to do to the film. The Scan Station does an excellent job and it is very consistent and every place has one or two of them so the cost associated is allot less than a much more costly and less widely available true RGB scanner like the Arriscan or Director.

[Joshua Echevarria]

46 minutes ago, Robert Houllahan said:

I know Metro has an older 4K Director I am not sure how that compares to the current Scan Station you could probably talk to Jack at Metro about that.

New Directors use the 6.5K sensor but it is a monochrome one instead of color and has a piezo shift like the Arriscan to make 13.5K out of a 6.5K sensor. The older ones used a 4K monochrome CCD I am not sure how that performs but they did have 2-flash and 3-flash on them from the beginning.

As for comparisons you will have a hard time finding any and the film I am scanning now did allot of tests they spent the time effort and funds to compare the results for their film. I know Co3 NY has an Arriscan and Scannity but I do not think they take smaller jobs.

It really comes down to how much extra time and cost do you want to go to squeeze the very best out of the film and how much post finishing you plan to do to the film. The Scan Station does an excellent job and it is very consistent and every place has one or two of them so the cost associated is allot less than a much more costly and less widely available true RGB scanner like the Arriscan or Director.

ah yeah I didnt realize it was a 4k Director.  I would imagine for our film's budget which isn't super low but still relatively modest, an RGB scan might be out of the question unless we were to send the film out to Fotokem or elsewhere with the scanner I'd like to use

[Robert Houllahan]

39 minutes ago, Joshua Echevarria said:

ah yeah I didnt realize it was a 4k Director.  I would imagine for our film's budget which isn't super low but still relatively modest, an RGB scan might be out of the question unless we were to send the film out to Fotokem or elsewhere with the scanner I'd like to use

FotoKem and Co3 both use DFT Scannity and Arriscan scanners I do not think either company has any LaserGraphics scanners.

[Daniel D. Teoli Jr.]

 

On 1/7/2025 at 5:22 PM, Joshua Echevarria said:

I appreciate your insight.  

I'm up in the air right now.  Its for a short that is guaranteed a theatrical screening.  There is only 1 LG Director in NY that I know of.  Everyone else has a scanstation.    do you have any side by side comparisons?

You hit the nail on the head with what is needed Josh.

Commercial scan companies seldom do side by side comparisons. Generally, what you get here is all words. Robert and Perry are good academics, but they generally only deal in words. I'm visually oriented and deal in images, so I like to see visual comparisons.

When I printed the Encyclopedia of Inkjet Printing series, I gave the special collection institutions and museums a disc of hi-res files of all the images in the series. That way they could test future printing media releases to compare to the ones printed in the books. Scan companies are always upgrading their scanners. If they had any interest in side-by-side comparisons, they could have bought some public domain film off eBay and kept a file on these things. Or if they were actual film producers, they would use their own film examples for tests.

With regards to auto cleanup software...check this out.

Examples of image loss from Epson ICE scan D.D. Teoli Jr. A.C. : Daniel D. Teoli Jr. Archival Collection : Free Download, Borrow, and Streaming : Internet Archive

This is for still software, not movie software. Generally, you lose too much and have to do cleanup by hand to get good results. But my experience is limited.

Good luck!

<><><><>

Daniel D. Teoli Jr. Archival Collection
Daniel D. Teoli Jr. Small Gauge Film Archive
Daniel D. Teoli Jr. Advertising Archive
Daniel D. Teoli Jr. VHS Video Archive
Daniel D. Teoli Jr. Popular Culture Archive
Daniel D. Teoli Jr. Audio Archive
Daniel D. Teoli Jr. Social Documentary Photography

Edited January 9 by Daniel D. Teoli Jr.

[Robert Houllahan]

On 1/7/2025 at 7:30 PM, Joshua Echevarria said:

ah yeah I didnt realize it was a 4k Director.  I would imagine for our film's budget which isn't super low but still relatively modest, an RGB scan might be out of the question unless we were to send the film out to Fotokem or elsewhere with the scanner I'd like to use

I spoke to Jack at Metro yesterday and you should maybe reach out about a scan on his Director 4K it will be a excellent high quality true RGB scan and likely still offers the advantages of an RGB scan over the 6,5K Scan Station.

Alternatively if you want to DM me I could possibly scan on my Arriscan although I would have to figure out a schedule as I am in the middle of a selects scan on a 50 lab roll feature film on the Arriscan.

I would also say not to sweat the scanner too much as all of the machines in question make incredibly good scans.

Rob "academically" surrounded by film scanners and a busy film lab Houllahan...

[Perry Paolantonio]

2 hours ago, Daniel D. Teoli Jr. said:

Robert and Perry are good academics, but they generally only deal in words.

Pardon me?

[Joshua Echevarria]

25 minutes ago, Robert Houllahan said:

I spoke to Jack at Metro yesterday and you should maybe reach out about a scan on his Director 4K it will be a excellent high quality true RGB scan and likely still offers the advantages of an RGB scan over the 6,5K Scan Station.

Alternatively if you want to DM me I could possibly scan on my Arriscan although I would have to figure out a schedule as I am in the middle of a selects scan on a 50 lab roll feature film on the Arriscan.

I would also say not to sweat the scanner too much as all of the machines in question make incredibly good scans.

Rob "academically" surrounded by film scanners and a busy film lab Houllahan...

Thanks Rob

  our project isn’t shooting until mid Feb but I just learned that we do have a quick turnaround so I may have to keep things local to ny 

[Robert Houllahan]

3 minutes ago, Joshua Echevarria said:

Thanks Rob

  our project isn’t shooting until mid Feb but I just learned that we do have a quick turnaround so I may have to keep things local to ny 

Talk to Jack at Metro about the Director or maybe call Co3 NY or Postworks for Scannity or Arriscan scans.

[Perry Paolantonio]

58 minutes ago, Joshua Echevarria said:

  our project isn’t shooting until mid Feb but I just learned that we do have a quick turnaround so I may have to keep things local to ny 

If you decide you want to do it on the ScanStation (6.5k/HDR), get in touch with us - we don't offer rush services per se, but because most of our clients are archives with long project deadlines, we have the flexibility to do fast turnaround on most scanning-only jobs. Typically 1-2 days. We're in Boston, so UPS Ground from NY is overnight to get the film here and back. 

Edited January 9 by Perry Paolantonio

[Daniel D. Teoli Jr.]

On 1/6/2025 at 8:38 AM, Perry Paolantonio said:

Sequential RGB uses a monochrome sensor to make the image. Three images are taken, each with a different color light - Red, Green, Blue. The three channels are combined into a color image. Doing it this way you can do 16 bits per channel, assuming the sensor in the camera is 16 bit. If you bring a color image into Photoshop and look at the R/G/B channel separately, they're represented as monochrome images. This is the same thing, but in reverse. 

The ScanStation uses a faster Bayer sensor, but with 2-flash HDR and oversampling, the results are in many cases pretty comparable to a sequential RGB scan, in terms of bit depth.

IR is only used to create a dirt map that some restoration software can use. In the case of the Director, DICE is built in, so it uses that to do some in-scan cleanup of dirty film. If we had a director, we probably wouldn't use it, because it's not very good and it's baking those "corrections" into the image. But you don't have to have the cleanup done in-scanner. You can just output the straight scan along with a dirt map. This is handy, if your restoration software supports it. The basic idea is that any dirt that's physically on the film will not allow the IR light to pass through. the dirt map is a black and white image, with spots representing the location of the dirt on that frame. It's a second scan made at the same time, to a separate folder. The restoration software (if it supports it) can load that IR map up, and only target fixes where the dirt is. 

Of course this all sounds great, but doesn't account for dirt that's baked into a print (say, something that was on the negative, then got printed into the film). In that case, it's part of the picture, not physical dirt on the film, so it won't show up on a dirt map. But it can really speed up cleanup on dirty prints because you're not processing the entire frame, just the spots where there's actually dirt. 

If you are serious about spotting dust and defects you magnify the frame in small sections to clean up. You don't depend on dust maps. But that is for still work. You can't do this level of dust spotting with cine' film, nor should you. With still work, the single frame is studied and studied. With cine' work, the frame is gone in a fraction of a second. 

Selection from

Anatomy Of An 8mm Cine' Kodachrome

D.D.Teoli Jr.

BTW...this was photographed with a flatbed scanner, not a camera. That was why it had so much dust to clean up.

Edited January 10 by Daniel D. Teoli Jr.

[Perry Paolantonio]

30 minutes ago, Daniel D. Teoli Jr. said:

If you are serious about spotting dust and defects you magnify the frame in small sections to clean up. You don't depend on dust maps. But that is for still work. You can't do this level of dust spotting with cine' film, nor should you. With still work, the single frame is studied and studied. With cine' work, the frame is gone in a fraction of a second. 

Have you done restoration using digital restoration software on motion picture film, Daniel? If not, please stop comparing it to still image processing. It is decidedly not the same thing. If you cleaned up every frame of a movie in the same way you did a still image, the result would be an utter disaster -- totally unwatchable. Because, motion. 

As for dust maps, the question was asked what the IR pass is for, so I answered that. In reality, as I pointed out, it's only marginally useful, and it's only good for certain types of dirt.  As Rob mentioned, it's not used often. Many restoration tools don't support dustmaps - MTI does, PFClean does. Phoenix, which we use, does not. I don't know about Diamant. Dustmaps were something that came about 25+ years ago, as a way to speed processing on older computers by limiting the areas processed to those that needed it. This resulted in a better image because you didn't have to analyze the whole frame, which took forever, and the fixes were concentrated only in small areas. There were fewer false positives detected, and that means fewer errors.

Most digital motion picture restoration tools work by analyzing the motion in the current frame and surrounding frames and algorithmically coming up with a best case replacement for the pixels there - ideally by pulling those pixels from a frame or two away from the current one, in the same part of the image. Almost always, these require some level of manual override or adjustment. 20 years ago, when I restored my first feature film, the processing power required to do this was enormous and it took over a month to do a feature length film in HD - not even 2k or 4k. For that reason, dust maps make sense in some situations. But nobody has ever said that's the only way to do it. today, on hardware that's orders of magnitude faster, it still takes about a month for one person to do a pristine restoration manually, sometimes longer. All depends on the film. 

Please stop comparing motion picture tools to still image tools. There are some overlaps but they're not the same and you can't compare the two. 

Edited January 10 by Perry Paolantonio