DPR Forum

Welcome to the Friendly Aisles!
DPRF is a spin-off of dpreview. We are a photography forum with people from all over the world freely sharing their knowledge and love of photography. Everybody is welcome, from beginners to the experienced professional. From smartphone to Medium Format.

DPRF is a community for everybody, every brand and every sensor format. Digital and film.
Enjoy this modern, easy to use software. Look also at our Reviews & Gallery!

What Actual Megabyte Size Should Negative Scans Be

Hi Mike,
You are right and wrong, only the high contract prepress camera lens has the resolution that you mention. And the scanner with 15000ppi(around 600ppm)is for the use of electronic/chip industry and not for color film scanning. To take 6M pixels in 36x24 film, it is equel to 83 pixel per mm (pixel mean the spot with RGB information). DO you mean 40M file (RGB Tiff) or 40M pixels file (=120M file RGB Tiff)? By the way, if you would like to scan the color of each dye on each layer of film, you may need a higher for 135film (as the Pro Photo CD resolution). But as I state before the "image information" is still around 20M (a group of dye particles carry same set of information due to limit of lens resolution). Kodak has the extensive study in determine which is the optimal resolution for film scanning when Kodak developed PhotoCD system and what I write here was the summary from the result.
CCD is a hot items during these ten year and ton of money had been spent in new CCD technology. So the SN is better and so the dynamic is now better than several year ago. Here is a good ex&le. Imacon scanner is the professional scanner using CCD technolgoy and for desktop publishing. They using Three Ccd for different color scanning. Between the CCD and the film is a ultra high resolution lens for focusing and fit for different size of film. For 35mm film, the high resolution is 222ppm. I do have the experience in checking several scanner with the same scanning resolution, they produce different resolution image. Some scanner need to increase scanning resolution in getting compartable image. There are too many factors affecting the image. But please chk to scan b/W image using color mode to cross chk if the scanner is using color moasic filter over the ccd and do the interpolation color information.
In designing CD audio, the enginner of Philips using a lot of effort in squeezing 70mins audio information into 650M disk so they need to give up many thing such as the information between each s&le data (the information inbetween the s&le is reconstructed afterward. Audio is analog signal and record in digital media. High s&le freq means more accurate reflect the sound. Bit equals to dyanamic of scanner. True is that SACD produces better sound. However, in scanning industry, drum scanner already be here more than 15 years and there is not the issue as cd audio development.

Last but not least, there is a different theory about the film resolution. The true is that the resolution of movie film is not very high. But the random pattern of dye in different frame makes the preceive resolution of the projection image become very high. The IEEE image is for digtal film production and need 32bit (even 48).
 
Hi Leo,

I've definitely seen 15000ppi scanners that are intended for colour repro use (ISTR there are Tango and ICG models that will reach this resolution, although they carry six-figure price tags). However, I tend to agree that the benefit seems questionable with general-purpose film, and that they probably find their most appropriate applications in photolithography and other technical niches.

Yes, I did mean 40Mpixels (=120MB for 8-bit-per-pixel uncompressed RGB tiff). Your point about Kodak's research results for PhotoCD mirrors what I said about 16-bit PCM audio -- in the end both formats were constrained by the practical limitations of their day, and the designers were trying to avoid squandering resources or creating requirements for expensive parts in the implementations. We are lucky that we are not tied to a fixed file format for distribution in the way that audio people have to live with redbook CD-audio, but it makes no sense to stick with a 6M pixel standard for 135 format scans. 83 pixels per mm is 41.5 line pairs per mm, and there are many lenses that will provide useful contrast values at higher frequencies than that (though not up to 100lpmm!)

I agree fully on the other points about the impact of the scanner optics and the type of CCD implementation. Light source can also be added to that list (I've never had a close look at Imacon scans of B&W film, but I imagine they must be super-hard with the type of light source they use). Also, it's very interesting what you say about the time-domain effect of movie film projection creating an increase in perceived resolution, that makes a lot of sense.

TTFN

-= mike =-
 
Hi Mike,
You may not believe that the light source of Imacon is a on-the-shelf fluoresce tube!! The spectrum is not continuous. However, the matching table is good and can normalize the data.
Kodak's highend scanners are using
1. halogon/tunsgten (older model
2. LED
The 1. is the expensive solution since a big heavy duty powersupply is needed to supply stable voltage to the l& so the color temp can be maintained.
2. LED is a newer solution of the light source.

However, cool light is the best option when considering cost, lifespan and stability. So, why all consumer/prosumer scanners are using cool light source.
But Scitex and Imacon are using coollight source very well but still not the best.
Recently you may know that the digital camera is going to 1x million pixels. Using same philosophy, the optimal resolution of digital SLR camera is 18million pixels (3 x 6millions).

Let share

Leo
 
>Posted by Leo Jar on Wednesday, July 30, 2003 - 7:01 pm: > >Hi Mike, >You may not believe that the light source of Imacon is a on-the-shelf >fluoresce tube!! The spectrum is not continuous. However, the matching >table is good and can normalize the data. >Kodak's highend scanners are using >1. halogon/tunsgten (older model >2. LED >The 1. is the expensive solution since a big heavy duty powersupply is >needed to supply stable voltage to the l& so the color temp can be >maintained. >2. LED is a newer solution of the light source. > >However, cool light is the best option when considering cost, lifespan >and stability. So, why all consumer/prosumer scanners are using cool >light source. >But Scitex and Imacon are using coollight source very well but still >not the best. >Recently you may know that the digital camera is going to 1x million >pixels. Using same philosophy, the optimal resolution of digital SLR >camera is 18million pixels (3 x 6millions). > >Let share > >Leo

I can't quite understand the last paragraph. Can you re-state it?

Thanks,

DAW
 
Hi DAW
Due to the limitation of the lens resolution (since the digital SLR camera is still using conventional lens), the optimal pixels number is 18million. In real life, the pixel count is based on the total of pixel number and they are monochromic sensitive. So RGB filters should be placed on each pixel. By mathamatics calculation (interpolation), the camera will reproduce the full color information on each pixel. (so why the cameras will have different in image quality even they are using the same CCD. They may using different method in calculation)

thanks,

leo
 
Hi Folks,
I got in touch with the firm and they are 18 meg scans. I also bought and Epson 1290s and printed a couple of them out on the supplied epson paper. They are quite marvelous, maybe not as good as a traditional darkroom, but very acceptable. I will not bother sending them to the lab to have them processed. I will leave the lab for the really good/big stuff if I ever need to go that route again

Thanks for the information.

Paul.
 
Help please
I am completely new to digital printing and I have trouble sizing images to fit paper size
I had some images scanned and the files are 50mb
I open the image in Photo Elements and print preview shows me a 1.5 x 1.5 inch image in the middle of the screen

I cannot get the image to adjust to A4 size without the scale going to 500%+ and I get a piece of the image printed

I may be doing something very elementary incorrectly

how can I correct this problem. I have tried all boxes in Page Set UP , res&le image, Resizing Image etc

thanks

when I go to print them I cannot get the files
 
Hi if you are useing photo shop, and I assume elements works the same way. First you must resize the canvers or the image will be croped to fit on the original canvers. If you are useing an epson printer and prin your original file useing epsons soft ware the image will be re sized automaticaly.
Hope this helps John.
ps I use a CanoScan 2700f and the twain inerface on that can be used to out put a printer file as opposed to a direct(100%)2700 dpi file
 
Back
Top