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In the 1980s, glossy prints from mass-market photofinishers were the exception, not the rule.

That wasn't my experience.

I remember silk finish being an option, on request, but never mandatory.

 

It's true that pictures from a 126 Instamatic probably don't warrant more than 300 ppi scanning. OTOH something like a little Olympus XA is capable of excellent detail rendering. You also have to bear in mind that the resolution of a copy has to be greater than that of the original in order to retain all of the detail that's in the original.

 

I honestly don't understand what the problem would be with scanning at 600 ppi. It's the native resolution of many low end flatbed scanners, and won't slow the process down by much, if at all. And as mentioned before, computer storage is cheap and plentiful these days. So that even the average 'laptop' computer won't baulk at processing an 8 Mpx file... or several.

And keep in mind that the flash memory in those devices isn't archival.

Just to be clear; I was in no way suggesting using flash memory of any sort for archival storage. I was only giving an example of how little storage is needed for an 8 megapixel file.

Edited by rodeo_joe|1
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Re-reading your OP, I agree with [uSER=2403817]@rodeo_joe|1[/uSER] that 300 dpi should be fine for photos of 15 x 10 cm and 600 dpi would be an overkill, just giving you file sizes 4 times as large for no real benefit. A 15 x 10 photo scanned (and cropped to size) at 300 dpi would be about 2 MB. The same photo scanned at 600 dpi would be more than 8 MB.

 

The only reasons I can see to use 600 dpi is you scan photos that have physical damage in 'sensitive areas' (faces) or small prints like 6 x 6 cm. The 'optical sharpness' is also worth considering. If film photos are really sharp (or have very small details) then 600 dpi could help to preserve this/these. For photos taken on 'not very expensive cameras' this is perhaps unlikely.

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For some photos, it can be useful to use a more precise method than 'eyeballing it' (which is quicker!):

- add a threshold layer and move the slider from left to right to find the 'blackest points'; mark one of these this with the color sampler tool

- move the slider from right to left to find the "whitest points"; mark one of these with the color sampler tool too

- add a new layer above the photo, fill it with 50% grey and set the blending mode to "difference"; go back to the threshold layer and move the slider from left to right to find the 'grey points'; mark one of these with the color sampler tool

 

Hide the threshold and grey-filled layers and add a curves layer. In the curves layer, you can set the black, grey and white points based on the color sample points. This should correct the color too.

 

Scanning prints at resolutions higher than 300 dpi doesn't reveal more detail, but I scan them at 600 dpi to allow future 2-3x enlargements from the digital file. For example, scanning a 4x6-inch print at 600 dpi produces enough resolution to make an 8x12-inch print or even a little bigger without pixelation. Higher resolutions theoretically permit even greater enlargements, but sharpness falls off dramatically after 2x.

 

Scanning to JPEG instead of TIFF is okay if you make the major adjustments in the scanner software before scanning. The scanned file should then be very close to ideal and require only minor adjustments that won't reveal the limitations of an 8-bit JPEG file. I've scanned thousands of prints this way. But the scanner software included with all-in-one (AIO) printer/scanners may not allow you to make many adjustments before scanning. Switch to "Advanced Mode" or "Manual Mode" if it has one.

 

An AIO printer/scanner is probably good enough for scanning snapshot-size prints made with old cameras. I doubt you'd see much improvement with a dedicated scanner.

 

Hint: old color prints are usually faded. A quick way to restore the color balance is to use the histogram-levels control in the scanner software, if it has one. Usually these controls have three "eyedroppers" under the histogram: black point, midpoint, and white point. If you can find something that should be a middle-gray tone in the picture and click on it with the midpoint eyedropper, all the colors should change to something more natural. The middle-gray tone could be concrete in an outdoor picture, an article of gray clothing, or even gray hair. It may take a few tries to find the right spot, but you can undo each wrong try. This method works better than tweaking the individual color controls unless you have unusually good color perception.

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It's true that pictures from a 126 Instamatic probably don't warrant more than 300 ppi scanning. OTOH something like a little Olympus XA is capable of excellent detail rendering. You also have to bear in mind that the resolution of a copy has to be greater than that of the original in order to retain all of the detail that's in the original.

 

Yes, the Olympus XA was so good that after losing one on a camping trip, I bought another. But they were mostly owned by advanced amateurs. Some higher-end Instamatics weren't too bad. Most were terrible. My grandmother's 1914 Kodak box camera made better pictures than the typical Instamatic, mainly because the prints were contacts, not enlargements. The real boon for snap shooters was the introduction of compact 35mm cameras with autofocus, built-in electronic flash, and easy loading.

 

I honestly don't understand what the problem would be with scanning at 600 ppi. It's the native resolution of many low end flatbed scanners, and won't slow the process down by much, if at all.

 

I agree. If a 4x6-inch snapshot is well composed but unsharp, I'll scan it at 300 dpi, good enough. But most are poorly composed, so I'll scan at 600 dpi and crop it for a better composition, which leaves something like 400-500 dpi.

 

BTW, I also tested the optimal resolution for copy prints made at Walgreens. To make a 4x6-inch print, I uploaded the same image at 300 dpi, 600 dpi, and 1200 dpi. The Walgreens prints showed no difference. So now I always scale them to 300 dpi, which is only 1200 x 1800 pixels, or 2.1 megapixels. They upload much faster and still look fine.

 

I don't know if the Walgreens machine automatically downsizes everything to 300 dpi or if their printer simply can't resolve more detail. Maybe other places such as Mpix or Shutterfly do better. I recently ordered a 12x12-inch photo book from Shutterfly that includes some low-res pictures made with a smartphone. Some of them are less than 300 dpi. The book hasn't arrived in the mail yet so I don't know how they'll look on paper.

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I have a Canon 9950F scanner which lets me scan slides, negatives and prints. I've used it with some success; however, I've had issues with being able to get images with enough quality to enlarge without significant grain. This scanner was last supported by Canon with Windows 7 - not sure about Apple. Fortunately I still have a Windows 7 desktop which I just reconnected to try the scanner again. I'm keeping my fingers crossed that I'm a little smarter and able to get better results this go around.
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What film are you using and how is it being processed?

 

Oh my, its been so long since I used film I don't remember much beyond using Kodachrome, Ektachrome, and sometimes black and white. I sent all of my color film out for processing but processed my own black and white in 1969 & 1970. I used my camera less and less starting in the early 70s through 2001 when I started using an early digital camera that was terrible - press the shutter button and while waiting for the shutter you could go out for dinner and a movie. I still have my old Canon T70 film camera with 4 lenses - 50mm f1.4; 24-36mm f3.5L; 35-105mm, f3.5 macro; 70-210mm f4 macro. I may grab the T70 and ask my granddaughter to go out on a shoot with her Canon F1.

 

I love black & white, but could convert color to black and white in post processing. I would appreciate any recommendations that you may have regarding film for my granddaughter and I.

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On a much more fundamental level of discussion --

 

There is a photographic equivalent of the carpenter's "measure twice, cut once".

 

Scanning images is a long and tedious process, so I very much recommend that you

"Scan once, scan large"

It takes very little more time to make a large scan than a low resolution scan, and storage is so cheap that filling up a storage device is hard to do.

You can always downsize without any real problem, but going the other direction sucks.

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On a much more fundamental level of discussion --

 

There is a photographic equivalent of the carpenter's "measure twice, cut once".

 

Scanning images is a long and tedious process, so I very much recommend that you

"Scan once, scan large"

It takes very little more time to make a large scan than a low resolution scan, and storage is so cheap that filling up a storage device is hard to do.

 

You can always downsize without any real problem, but going the other direction sucks.

 

I think I agree for film, but maybe not for prints.

 

Some time ago I was scanning film, and then an 8x10 print with a 3200 dpi scanner.

 

The scanner will scan the print at that resolution, but the file is huge (even by today's standard)

it does take a long time, and I suspect the print doesn't have that much resolution.

-- glen

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and I suspect the print doesn't have that much resolution

That depends on the size of the original film. A contact print from 10"x8" sheet film will obviously have more detail than an 8x enlargement from a 35mm frame.

 

In the latter case, no, the print definitely won't contain 3,200 ppi's worth of detail.

 

As a rule of thumb, a scan equal to 4,000 ppi from the original negative will garner all the detail that's available. E.g. with a 10x8 blowup from 35mm that would be 4,000/8 = 500 ppi, and even that might be mainly 'empty pixels'.

 

Not to mention that a claimed 3,200 ppi 'true optical resolution' is really no such thing when dealing with most flatbed scanners.

 

One has to use a little common sense when deciding on a scan resolution.

Edited by rodeo_joe|1
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That depends on the size of the original film. A contact print from 10"x8" sheet film will obviously have more detail than an 8x enlargement from a 35mm frame.

 

In the latter case, no, the print definitely won't contain 3,200 ppi's worth of detail.

 

As a rule of thumb, a scan equal to 4,000 ppi from the original negative will garner all the detail that's available. E.g. with a 10x8 blowup from 35mm that would be 4,000/8 = 500 ppi, and even that might be mainly 'empty pixels'.

 

Not to mention that a claimed 3,200 ppi 'true optical resolution' is really no such thing when dealing with most flatbed scanners.

 

One has to use a little common sense when deciding on a scan resolution.

 

I am pretty sure I don't have any 8x10 contact prints.

 

It is possible that the scanner gives 27200 pixels in one scan line.

The chances that those are the right 27200, pretty small.

 

First, sampling theory requires delta function sampling at each sample point. Not likely.

 

Next, it somehow has to image a line across the glass onto a line CCD sensor with some

combination of mirrors and lenses. Even if it does manage to get 27200 points, there is very

likely some distortion on where those points are. This tends to be fairly wide angle, so as

not to make the scanner too large. One could image a very exact array of lines

and determine the distortion in the pixel imaging.

 

Next, the scan head is moved down the length of the negative or print, with some combination

of pulleys and gears. To fit within the usual sized box, there is a mirror that moves at half the

speed of the scanning head, that reflects onto the sensor. There is then a system to compute

the position of the scan head to, hopefully, close to scanner resolution. (That is, it actually

does some scanning.)

 

In a sort-of best case, it integrates each pixel of 1/3200 inch square, which applies a spatial

filter to the actual source. Hopefully the source doens't have much more resolution, so we

don't get any aliasing. Reasonably likely the optics aren't that good, so no problem there.

 

In case the desired scan is at less than sensor and scan head movement resolution, it needs

to downsample the image. That is, low-pass spatial filter to the new spatial frequency,

then select an appropriate value for each pixel. This can get close to the desired delta

function, but it is unlikely that they go through the math in both x and y to do that.

But maybe an approximation to the appropriate low-pass filter and sample point

selection.

 

For all those reasons, I try not to image 35mm frames on flatbed scanners.

 

A dedicated 35mm scanner usually images onto a line sensor with a lens,

and no mirrors. The distance can be reasonable, so less stretching the optics

of the lens system. Moving the film the appropriate distance between scans is

usually easier than moving the mirror/lens system for flatbed scanners.

 

I have a cheaper 35mm scanner that images the whole frame at once,

I suspect using a low-end 2D CCD sensor. Works fine for lower resolution

needs, such as screen resolution images. Maybe even for 4x6 prints.

Much faster than moving-film scanners.

 

Not to mention that once you have the scan, you have to do something with it that

might have more imperfections. There are digital optical printers that scan lasers

across AgBr based paper. Hopefully through lenses that come close to the

appropriate positions across the paper. As far as I know, 300dpi is usual.

-- glen

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It is possible that the scanner gives 27200 pixels in one scan line.

The chances that those are the right 27200, pretty small.

Huh?

Where does the very specific figure of 27,200 come from? And no tri-line CCD sensor yet made has that many photosites in a single line.

Also, how can pixels be the 'right' or 'wrong' ones?

First, sampling theory requires delta function sampling at each sample point. Not likely.

Gobbledegook.

Pixel sampling simply requires a mean brightness or density to be read and digitised from the area being sampled.

 

Pixels themselves are dimensionless and have no fixed size.

Next, it somehow has to image a line across the glass onto a line CCD sensor with some

combination of mirrors and lenses.....

I have no idea what the mechanics of a flatbed scanner have to do with selecting a suitable PPI (Pixels Per Inch) figure for scanning.

 

Note: Not DPI - Dots Per Inch only applies to half-tone or inkjet printing. The fact that Epson and other scanner makers persistently and perversely use the wrong terminology doesn't make it any more correct.

Edited by rodeo_joe|1
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Huh?

Where does the very specific figure of 27,200 come from? And no tri-line CCD sensor yet made has that many photosites in a single line.

Also, how can pixels be the 'right' or 'wrong' ones?

 

Gobbledegook.

Pixel sampling simply requires a mean brightness or density to be read and digitised from the area being sampled.

 

Pixels themselves are dimensionless and have no fixed size.

 

I have no idea what the mechanics of a flatbed scanner have to do with selecting a suitable PPI (Pixels Per Inch) figure for scanning.

 

Note: Not DPI - Dots Per Inch only applies to half-tone or inkjet printing. The fact that Epson and other scanner makers persistently and perversely use the wrong terminology doesn't make it any more correct.

 

27200 is 8.5*3200, and what Epson claims for the 3200 scanner.

They also claim interpolated as 12800 pixels/inch, I don't know how they do that.

 

The scanner is supposed to sample at equal distances across the source.

There is a lens between the sensor and source, which might have some distortion,

so the actual pixels might not be at the desired position. They could be many

pixels off from the desired position.

 

If you look at a small part of the image, this is unlikely to matter, so you still get a high resolution,

but those pixels could be shifted away from where they are supposed to be. In some very regular

sources, you might notice.

 

From sampling theory, if you sample a frequency limited source at more than twice the highest frequency,

you can exactly reproduce the original from the samples. If the samples are not at points (delta function),

but over a wider area, this acts like a low-pass filter on the image. If you don't mind that, that is fine.

 

By the way, sampling theory does not require equally space points, though it makes the math a lot

easier, and also makes reproduction easier. (Besides that sampling theory only works for periodic

or infinite length sources.)

 

Sorry about using the way too common dpi.

-- glen

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27200 is 8.5*3200, and what Epson claims for the 3200 scanner.

Epson claim a lot of things - like 3200 dpi (sic) 'true optical resolution' - that are pure hyperbole.

From sampling theory, if you sample a frequency limited source at more than twice the highest frequency,

The Nyquist limit only applies to the maximum frequency that can be captured before aliasing occurs. This is a spatial frequency in the case of a scanner, so 3200 samples per inch can theoretically capture 1600 line-pairs-per-inch. This is about 63 lppmm, and far more detail than could reasonably be expected in any 10"x8" print.

 

WRT distortion: Not a practical issue IME. You can scan graph-paper with most scanners and get a very close match to the original spacing.

 

However, I'd still question the claim of 3200 ppi across the whole of an 8.5" platen. When I cared about such things I scoured the data sheets of all the tri-linear CCD sensor manufacturers (Toshiba, Sharp, Dalsa, Kodak, etc.), and could find nothing that offered more than 10,200 pixels across its length. This would give a 'resolution' of 1200 ppi over 8.5".

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It is hard to find so much detail, but it does seem that Epson uses 6 line CCDs.

It might be that three rows are offset by half, such that it can get the higher resolution.

 

I haven't looked for the data sheets on them.

 

As for distortion, I suspect that it isn't really an issue, but it does complicate the meaning

of resolution if you use the correct meanings of accuracy and precision.

You can have one without the other.

 

If I have a tape measure with 1mm divisions, I expect to be able to measure things with

accuracy close to 1mm. Sometimes I don't need so much accuracy, but only need

precision.

 

Practices of Science: Precision vs. Accuracy | manoa.hawaii.edu/ExploringOurFluidEarth

 

Just saying resolution doesn't say whether it is accurate and/or precise to that value.

-- glen

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Just saying resolution doesn't say whether it is accurate and/or precise to that value.

I totally agree.

 

From browsing Epson's website, it appears that you're quoting the specification for their Perfection V100 scanner. This scanner sold for about £70 UK, and if the specification is to be believed, it potentially out-resolves their V800 Pro model at ten times the price. I find that highly unlikely and difficult to believe.

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I didn't look for the V800, but have the service manual for the V700.

 

(Which doesn't say near as much as it should.)

 

The V700 says "4800dpi optical resolution". (yes, it says dpi) at 8.5in for 40800 pixels,

or 6400dpi times 5.9in for 37760 pixels.

 

(Maybe the manuals are made by the same people that make the printer manuals.)

 

It seems that it switches lenses between the two modes. It does say it is a six line sensor,

but doesn't give details on those lines. My guess is six lines of 20400 pixels spaced such

that it can scan like three lines of 40800 pixels. (Reminds me of how printers work.)

 

The one I have is the model 3200, where it seems to be numbered after its "3200dpi"

(quoting Epson again). I believe it is older than the V series, but might have been at

a similar place in the product line, at the time.

 

For many scanners, the back light for transparency scanning is not the full width that

it uses for reflection scanning. That might be where the 59 inch comes from.

-- glen

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The V800: Epson Perfection V800 Photo Color Scanner | Photo and Graphics | Scanners | For Work | Epson US

 

actually says "Alternative 6 lines color Epson MatrixCCD®" so I think that agrees with what I said above.

 

There are also scanners which switch the light source color, instead of color filters on the sensor, but I

don't think that is what these do. (More usual for moving film scanners.)

-- glen

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It is hard to find data sheets, but I found the ILX137K:

 

ILX137K (SONY) PDF技术资料下载 ILX137K 供应信息 IC Datasheet 数据表 (1/13 页)

 

Which seems to be designed for (so it says) 2400dpi scanners.

 

As above, it has six rows, two of each color offset by half a pixel,

of 10700 pixels each. There are microlenses, but it doesn't say

what it does with them.

 

Many of the web sites are in Chinese, making it harder to read them, though

the actual data sheet is in English.

-- glen

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It is hard to find data sheets, but I found the ILX137K:

 

ILX137K (SONY) PDF技术资料下载 ILX137K 供应信息 IC Datasheet 数据表 (1/13 页)

 

Which seems to be designed for (so it says) 2400dpi scanners.

 

As above, it has six rows, two of each color offset by half a pixel,

of 10700 pixels each. There are microlenses, but it doesn't say

what it does with them.

 

Many of the web sites are in Chinese, making it harder to read them, though

the actual data sheet is in English.

Thanks for that link Glen.

As I suspected, the horizontal pixel number is just over 10,000; making the PPI figure over 8.5" about 1200. Not too bad for a relatively cheap scanner, and total overkill for most reflective copying purposes.

 

The six (2 by 3) rows of photosites appear to have the purpose of speeding up the scan time, by increasing the distance between scanning steps. There's no way it can improve resolution in the direction of scan that I can see. Which must remain at 1200 ppi due to the line spacing.

 

So, once again Epson are found out in their distortion of the truth.

There are microlenses, but it doesn't say

what it does with them.

Microlenses are there to increase light efficiency - so called 'fill factor'. That's always their sole purpose.

Edited by rodeo_joe|1
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Thanks for that link Glen.

As I suspected, the horizontal pixel number is just over 10,000; making the PPI figure over 8.5" about 1200. Not too bad for a relatively cheap scanner, and total overkill for most reflective copying purposes.

 

The six (2 by 3) rows of photosites appear to have the purpose of speeding up the scan time, by increasing the distance between scanning steps. There's no way it can improve resolution in the direction of scan that I can see. Which must remain at 1200 ppi due to the line spacing.

 

So, once again Epson are found out in their distortion of the truth.

 

Microlenses are there to increase light efficiency - so called 'fill factor'. That's always their sole purpose.

 

The rows are one half pixel offset, to get in between. That one claims 2400dpi

I believe that the elements are. close to the full width, so a funny spatial frequency response dip,

but you already said that doesn't bother you. I am not sure which scanner uses that one.

 

I haven't found the data sheet for the ILX185K, though, but I believe that one has twice as many for 4800 across 8.5in.

-- glen

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