TIFF 24 bit vs JPEG 24 bit for scanning color negative.

[Charmander]

I am scanning my color negative films for archival purpose and I came across some posts suggesting TIFF format because it is lossless.

My question is, since both format are of 24 bit (8 bit channel)

Wouldn't the quality be same ?

If I want to edit JPEG losslessly, I can always convert it to TIFF and can edit as much as I want without loosing any quality.

So there isn't any point of scanning in TIFF and utilising TON of space necessarily.

Am I right ?

Note:- (I am not using 48 Bit TIFF because of its insane size)

[davescm]

Jpeg reduces filesize by compressing the image data. It does this in a way that permanently loses that data, i.e. you never get it back. The quality can be good but if it is then adjusted and resaved - the compression works again , throwing away more image data.  It is a great format for sharing images, for example on websites where filesize is very important.  But not great for saving images that may be worked on later.

For that I would save as TIFF. Hard drive space is very cheap these days - compared to the early days of digital.

Dave

[D Fosse]

charmander  wrote

Note:- (I am not using 48 Bit TIFF because of its insane size)

I would never even consider saving master files as anything less than 48-bit PSD/TIFF. That's just a given. For exactly twice the file size, you get 16384 individual levels per channel to work with, instead of a mere 256. That's a bargain if you ask me.

Jpeg is not a working format. It is a final delivery format where bandwidth is a consideration, such as for web and email. A jpeg should never be resaved if avoidable.

My master file archive (mainly PSD) is by now around 20 000 files and several terabytes. Plus about 60 000 raw files. Yes, I've had to change drives and migrate the whole thing several times, but that's just the way it is. On the good side I've never seen a hard drive failure - I don't keep them that long.

[Charmander]

Yup, you are right.

48 BIT TIFF give a superior quality compared to 24 BIT TIFF.

But what about time ?

Will scanning at 48 bit take longer timethan 24 bit ?

[Per Berntsen]

But what about time ?

Will scanning at 48 bit take longer timethan 24 bit ?

I have no expereince with scanning in 24-bit, but my guess is that scanning times will be longer in 48-bit because there is twice as much data to process.

Why don't you try it and see for yourself?

[Conrad_C]

What you're missing is that the time the quality goes down is when the scan originally gets saved as a JPEG. You aren't going to get it back by converting it back to TIFF. In reality, the visible difference is probably not going to be that much if the JPEG was saved at or near maximum quality. But if you try to save more space by saving original scans at less than a very high quality JPEG level, then the visual artifacts of lossy JPEG compression are going to be more visible. You never get those compression artifacts when an original scan is saved to TIFF.

I'm actually scanning color film right now, same way I have for years: To 16 bits per channel TIFF files. But after I've scanned a roll of film, I batch export copies as TIFF with ZIP compression, and those become the 16bpc final masters. The ZIP compression saves a tremendous amount of drive space. (I'd do it in the scanning software, but it only supports LZW compression.) No, it's not as small as JPEG or an 8-bit TIFF, but storage is relatively cheap; I just bought a 4TB hard drive for only $99.

One way that I save space, when it makes sense, is to scan at a resolution lower than my scanner's maximum. I'll do this if a film frame is out of focus, has motion blur, or when the subject is not of much value. I'll set the scanner to half resolution or less, which is still more than enough for 1080p HD and web sharing, but saves a ton of storage space compared to maximum resolution.

Regarding 8-bpc vs 16-bpc: 8bpc may be OK if the scans look pretty close to perfect from the beginning. But the more you expect to correct color or dig detail out of shadows after the scan, the better 16bpc will work out.

[davescm]

Good point on the resolution. On many flatbed scanners the maximum output resolution is achieved by interpolation and is higher than the real optical resolution. There is no point in going beyond the resolution that you can achieve optically.

Dave

[Conrad_C]

I'm actually talking about choosing a resolution below the optical resolution of the scanner. I'll look at a frame and think "This snapshot is blurry, there's obviously less than 4000 lines of resolution in this frame." That's when I'll crank it down. Though sometimes it's faster to batch scan at maximum optical resolution and downsample blurry frames later if I want to save the space.

[Per Berntsen]

davescm wrote:

On many flatbed scanners the maximum output resolution is achieved by interpolation and is higher than the real optical resolution. There is no point in going beyond the resolution that you can achieve optically.

Yes, many consumer and prosumer flatbeds claim a resolution of 6400 or even 9600 ppi.

Tests have shown that even the best ones (Epson) have a real resolution of around 2200 ppi, so scanning at more than 2400 is a waste of time and disk space.

If the OP has one of these scanners, and for instance scans a 6 x 7 negative at 6400 ppi, 48-bit, the file size for an uncompressed tiff will indeed be "insane" - 1.33 GB. But at 2400 it will only be 191 MB.

I'm guessing that https://forums.adobe.com/people/Conrad%20C is using a dedicated film scanner (Nikon?) and film scanners usually deliver the advertised resolution.

[Nexahs1138]

They wouldn't be the same as they are both two completely different options. JPEG is a web format that is used for uploading images, TIF is similar to standard PSD.

As regards to scanning, it will goes as fast as your scanner can, it's not going to take 5 minutes to scan one section for TIF and 5 seconds for JPEG, that's just not how scanning works,