JPEG To TIFF (Again)

"Pedro" wrote in message

I read the explanations about the above (which were very informative), but I had some more questions that I would be grateful for someone answering.
I am restoring some old B&W photos and am using PS CS2. I have scanned quite a few of the photos in Jpeg and in grayscale. In reading Katrin Eismann’s book on restoring, it is clear I should have scanned those old photos in Tiff to get 16 bit depth and in RGB to take advantage of the restoration techniques that use the RGB individual color channels. However, I would like to avoid rescanning, except where absolutely necessary.

If I change the mode of the scanned photos to RGB from grayscale in Photoshop, will the effect be much different than if I scanned first to RGB? Also, will changing the depth from 8 bit to 16 bit in Photoshop be much different than if I scanned the photos first in 16 bit?
Thank you in advance for any advice you can give me.

Pedro,

I do this a lot and I find (personally) that a high scan resolution has more of an effect than colour depth. Are you scanning an image in the scanner software, saving it as a file, then opening the image in PS or are you using the File>Import>(Scanner name) command in PS?
If the latter, you will merely be importing a stream of pixels (the more the merrier) that hasn’t got a file type assigned to it, until you do a save. So in this scenario it would be the amount of pixels that you import that would be the important consideration. Once imported, you apply whatever colour space/depth/image mode you need to to achieve your ends. If you are doing the former, then it would be better to save the file as TIFF as this format uses a lossless compression algorythm so no scanned data is lost.
I don’t see 16 bit as being an advantage and have yet to see any discernable difference in output quality on the size of image I work with. Also, you will be reducing the amount of filters, as not all will work in 16 bit.

HTH
MH

Thanks for the reply, Mike. With all of what you said, can I avoid rescanning by just changing the mode of the already scanned Jpeg files to 16 bit and RGB? I realize I need to change the format to Tif in order to get 16 bit. Or put another way, will the current scans give me the same channels and or 16 bit depth as if I had scanned to a Tiff file if all I do is change the mode to RGB and 16 bit via Photoshop?

Lastly, I’d appreciate your advice on what resolution to scan prints and slides that I plan to restore. I have access to a separate film scanner for the slides.

Thanks again.

Pedro.
"Mike Hyndman" <tell me yours and I’ll send > wrote in message

"Pedro" wrote in message

I read the explanations about the above (which were very informative), but I had some more questions that I would be grateful for someone answering.
I am restoring some old B&W photos and am using PS CS2. I have scanned quite a few of the photos in Jpeg and in grayscale. In reading Katrin Eismann’s book on restoring, it is clear I should have scanned those old photos in Tiff to get 16 bit depth and in RGB to take advantage of the restoration techniques that use the RGB individual color channels. However, I would like to avoid rescanning, except where absolutely necessary.

If I change the mode of the scanned photos to RGB from grayscale in Photoshop, will the effect be much different than if I scanned first to RGB? Also, will changing the depth from 8 bit to 16 bit in Photoshop be much different than if I scanned the photos first in 16 bit?
Thank you in advance for any advice you can give me.

Pedro,

I do this a lot and I find (personally) that a high scan resolution has more of an effect than colour depth. Are you scanning an image in the scanner software, saving it as a file, then opening the image in PS or are you using the File>Import>(Scanner name) command in PS? If the latter, you will merely be importing a stream of pixels (the more the merrier) that hasn’t got a file type assigned to it, until you do a save. So in this scenario it would be the amount of pixels that you import that would be the important consideration. Once imported, you apply whatever colour space/depth/image mode you need to to achieve your ends. If you are doing the former, then it would be better to save the file as TIFF as this format uses a lossless compression algorythm so no scanned data is lost.
I don’t see 16 bit as being an advantage and have yet to see any discernable difference in output quality on the size of image I work with. Also, you will be reducing the amount of filters, as not all will work in 16 bit.

HTH
MH

"Pedro" wrote in message

Thanks for the reply, Mike. With all of what you said, can I avoid rescanning by just changing the mode of the already scanned Jpeg files to 16 bit and RGB? I realize I need to change the format to Tif in order to get 16 bit. Or put another way, will the current scans give me the same channels and or 16 bit depth as if I had scanned to a Tiff file if all I do is change the mode to RGB and 16 bit via Photoshop?]

Pedro
If you have scanned and saved them as JPGs prior to manipulation. then you will have already lost some of the scanned data when you saved the file as a lossy JPG. When scanning, you need to extract every last ounce of information out of the scanned image (high res scan ) then save it in a lossless format, e.g., TIFF.
I tend to work with and restore old B & W images, sometimes "tinting" them or giving them an old sepia effect and 8bit RGB works perfectly well. These images, coming from the era when they were shot, would have had a much more limited colour palette anyway, (if at all) compared to what is available today.
Why do you need 16 bit? This is 281,474,976,710,656 colours, 8 bit is "only" 16.78 million colours.
If your final image size is quite small, (like for like?) you shouldn’t be unduly worried, I would just choose the Image mode required, 8 or 16 bit.(try it and see if you can see any difference) Old photos tend not to be the sharpest around in any case.

Lastly, I’d appreciate your advice on what resolution to scan prints and slides that I plan to restore. I have access to a separate film scanner for the slides.

I scan at the highest resolution (this differs according to "original" size) that my system memory will allow and is also dependant on what size I intend to print the finished file at. Transparencies need to be scanned at the highest possible setting if you intend to print higher than 10 x 8. It’s a "suck it and see" situation. 😉

Thanks again.

You’re very welcome, have fun!
Mike H

Pedro.
"Mike Hyndman" <tell me yours and I’ll send > wrote in message

"Pedro" wrote in message

I read the explanations about the above (which were very informative), but I had some more questions that I would be grateful for someone answering.

I am restoring some old B&W photos and am using PS CS2. I have scanned quite a few of the photos in Jpeg and in grayscale. In reading Katrin Eismann’s book on restoring, it is clear I should have scanned those old photos in Tiff to get 16 bit depth and in RGB to take advantage of the restoration techniques that use the RGB individual color channels. However, I would like to avoid rescanning, except where absolutely necessary.

If I change the mode of the scanned photos to RGB from grayscale in Photoshop, will the effect be much different than if I scanned first to RGB? Also, will changing the depth from 8 bit to 16 bit in Photoshop be much different than if I scanned the photos first in 16 bit?
Thank you in advance for any advice you can give me.

Pedro,

I do this a lot and I find (personally) that a high scan resolution has more of an effect than colour depth. Are you scanning an image in the scanner software, saving it as a file, then opening the image in PS or are you using the File>Import>(Scanner name) command in PS? If the latter, you will merely be importing a stream of pixels (the more the merrier) that hasn’t got a file type assigned to it, until you do a save. So in this scenario it would be the amount of pixels that you import that would be the important consideration. Once imported, you apply whatever colour space/depth/image mode you need to to achieve your ends.
If you are doing the former, then it would be better to save the file as TIFF as this format uses a lossless compression algorythm so no scanned data is lost.
I don’t see 16 bit as being an advantage and have yet to see any discernable difference in output quality on the size of image I work with. Also, you will be reducing the amount of filters, as not all will work in 16 bit.

HTH
MH

Dear Mike:

I am not the expert, but Katrin Eismann recommended having 16 bit depth. I would have to go back to her book to find out why she recommends it, but she does.

If we could move on to my other (non-16 bit) questions, I’d be grateful. Does changing the mode of a photo from grayscale to RGB create channels that are equal to the channels I would have gotten if I had scanned in RGB in the first place? Also, I’d appreciate learning from you what resolution you recommend scanning photos in, if they are scanned prints and separately if they are scanned slides. Your advice would be appreciated.

Thanks.

Pedro

"Mike Hyndman" <tell me yours and I’ll send > wrote in message

"Pedro" wrote in message

Thanks for the reply, Mike. With all of what you said, can I avoid rescanning by just changing the mode of the already scanned Jpeg files to 16 bit and RGB? I realize I need to change the format to Tif in order to get 16 bit. Or put another way, will the current scans give me the same channels and or 16 bit depth as if I had scanned to a Tiff file if all I do is change the mode to RGB and 16 bit via Photoshop?]

Pedro
If you have scanned and saved them as JPGs prior to manipulation. then you will have already lost some of the scanned data when you saved the file as a lossy JPG. When scanning, you need to extract every last ounce of information out of the scanned image (high res scan ) then save it in a lossless format, e.g., TIFF.
I tend to work with and restore old B & W images, sometimes "tinting" them or giving them an old sepia effect and 8bit RGB works perfectly well. These images, coming from the era when they were shot, would have had a much more limited colour palette anyway, (if at all) compared to what is available today.
Why do you need 16 bit? This is 281,474,976,710,656 colours, 8 bit is "only" 16.78 million colours.
If your final image size is quite small, (like for like?) you shouldn’t be unduly worried, I would just choose the Image mode required, 8 or 16 bit.(try it and see if you can see any difference) Old photos tend not to be the sharpest around in any case.

Lastly, I’d appreciate your advice on what resolution to scan prints and slides that I plan to restore. I have access to a separate film scanner for the slides.

I scan at the highest resolution (this differs according to "original" size) that my system memory will allow and is also dependant on what size I intend to print the finished file at. Transparencies need to be scanned at the highest possible setting if you intend to print higher than 10 x 8. It’s a "suck it and see" situation. 😉

Thanks again.

You’re very welcome, have fun!
Mike H

Pedro.
"Mike Hyndman" <tell me yours and I’ll send > wrote in message

"Pedro" wrote in message

I read the explanations about the above (which were very informative), but I had some more questions that I would be grateful for someone answering.

I am restoring some old B&W photos and am using PS CS2. I have scanned quite a few of the photos in Jpeg and in grayscale. In reading Katrin Eismann’s book on restoring, it is clear I should have scanned those old photos in Tiff to get 16 bit depth and in RGB to take advantage of the restoration techniques that use the RGB individual color channels. However, I would like to avoid rescanning, except where absolutely necessary.

If I change the mode of the scanned photos to RGB from grayscale in Photoshop, will the effect be much different than if I scanned first to RGB? Also, will changing the depth from 8 bit to 16 bit in Photoshop be much different than if I scanned the photos first in 16 bit?
Thank you in advance for any advice you can give me.

Pedro,

I do this a lot and I find (personally) that a high scan resolution has more of an effect than colour depth. Are you scanning an image in the scanner software, saving it as a file, then opening the image in PS or are you using the File>Import>(Scanner name) command in PS? If the latter, you will merely be importing a stream of pixels (the more the merrier) that hasn’t got a file type assigned to it, until you do a save. So in this scenario it would be the amount of pixels that you import that would be the important consideration. Once imported, you apply whatever colour space/depth/image mode you need to to achieve your ends.
If you are doing the former, then it would be better to save the file as TIFF as this format uses a lossless compression algorythm so no scanned data is lost.
I don’t see 16 bit as being an advantage and have yet to see any discernable difference in output quality on the size of image I work with. Also, you will be reducing the amount of filters, as not all will work in 16 bit.

HTH
MH

"Pedro" wrote in message

Dear Mike:

I am not the expert, but Katrin Eismann recommended having 16 bit depth. I would have to go back to her book to find out why she recommends it, but she does.

Pedro,
She is one clever lady and I am not gainsaying her, just merely stating what works for me, which is 8 bit. Ultimately, the choice has to be yours.Try both and see if you can any difference.

If we could move on to my other (non-16 bit) questions, I’d be grateful. Does changing the mode of a photo from grayscale to RGB create channels that are equal to the channels I would have gotten if I had scanned in RGB in the first place?

If you scan a B&W as a greycale image you will have an image with only 1 channel consisting of 256 levels of "grey"
If you scan the same image as an RGB image you will have 3 channels consisting of 256 levels each R, G & B. Thes channels will contain little colour information but some will be there in the form of discolouration/stains and colour casts due to the age and condition of the scanned print. (It is usualy easier to work on these sort of images in greyscale as you only have one channel to correct)
If you convert the single channel greyscale image to RGB in PS, you will get the three channels without any of the colour information that was originally present when first scanned (You never scanned it in the first place)So, to answer your question your converted image would not be equal to one scanned in RGB to start with.

Also, I’d appreciate learning from you what resolution you recommend scanning photos in, if they are scanned prints and separately if they are scanned slides. Your advice would be appreciated.

As I said earlier, the higher the better, it’s something you need to find out for yourself, no two images will present the same problem or have the same requirements.

Thanks.

What time zone are you in? I’m GMT and off to bed 😉
Talk manana?

Mike H

"Mike Hyndman" <tell me yours and I’ll send > wrote in message

"Pedro" wrote in message

Thanks for the reply, Mike. With all of what you said, can I avoid rescanning by just changing the mode of the already scanned Jpeg files to 16 bit and RGB? I realize I need to change the format to Tif in order to get 16 bit. Or put another way, will the current scans give me the same channels and or 16 bit depth as if I had scanned to a Tiff file if all I do is change the mode to RGB and 16 bit via Photoshop?]

Pedro
If you have scanned and saved them as JPGs prior to manipulation. then you will have already lost some of the scanned data when you saved the file as a lossy JPG. When scanning, you need to extract every last ounce of information out of the scanned image (high res scan ) then save it in a lossless format, e.g., TIFF.
I tend to work with and restore old B & W images, sometimes "tinting" them or giving them an old sepia effect and 8bit RGB works perfectly well. These images, coming from the era when they were shot, would have had a much more limited colour palette anyway, (if at all) compared to what is available today.
Why do you need 16 bit? This is 281,474,976,710,656 colours, 8 bit is "only" 16.78 million colours.
If your final image size is quite small, (like for like?) you shouldn’t be unduly worried, I would just choose the Image mode required, 8 or 16 bit.(try it and see if you can see any difference) Old photos tend not to be the sharpest around in any case.

Lastly, I’d appreciate your advice on what resolution to scan prints and slides that I plan to restore. I have access to a separate film scanner for the slides.

I scan at the highest resolution (this differs according to "original" size) that my system memory will allow and is also dependant on what size I intend to print the finished file at. Transparencies need to be scanned at the highest possible setting if you intend to print higher than 10 x
8. It’s a "suck it and see" situation. 😉

Thanks again.

You’re very welcome, have fun!
Mike H

Pedro.
"Mike Hyndman" <tell me yours and I’ll send > wrote in message

"Pedro" wrote in message

I read the explanations about the above (which were very informative), but I had some more questions that I would be grateful for someone answering.

I am restoring some old B&W photos and am using PS CS2. I have scanned quite a few of the photos in Jpeg and in grayscale. In reading Katrin Eismann’s book on restoring, it is clear I should have scanned those old photos in Tiff to get 16 bit depth and in RGB to take advantage of the restoration techniques that use the RGB individual color channels. However, I would like to avoid rescanning, except where absolutely necessary.

If I change the mode of the scanned photos to RGB from grayscale in Photoshop, will the effect be much different than if I scanned first to RGB? Also, will changing the depth from 8 bit to 16 bit in Photoshop be much different than if I scanned the photos first in 16 bit?

Thank you in advance for any advice you can give me.

Pedro,

I do this a lot and I find (personally) that a high scan resolution has more of an effect than colour depth. Are you scanning an image in the scanner software, saving it as a file, then opening the image in PS or are you using the File>Import>(Scanner name) command in PS? If the latter, you will merely be importing a stream of pixels (the more the merrier) that hasn’t got a file type assigned to it, until you do a save. So in this scenario it would be the amount of pixels that you import that would be the important consideration. Once imported, you apply whatever colour space/depth/image mode you need to to achieve your ends.
If you are doing the former, then it would be better to save the file as TIFF as this format uses a lossless compression algorythm so no scanned data is lost.
I don’t see 16 bit as being an advantage and have yet to see any discernable difference in output quality on the size of image I work with. Also, you will be reducing the amount of filters, as not all will work in 16 bit.

HTH
MH

"Pedro" wrote in message

Dear Mike:

I am not the expert, but Katrin Eismann recommended having 16 bit depth. I would have to go back to her book to find out why she recommends it, but she does.

When you saved the original as a jpg, you lost the ability to revert to 16 bits. It is true that you can specify the use of 16 bit mode, but you cannot restore the information that you discarded when you changed the image to 8 bit mode.
Jim

If we could move on to my other (non-16 bit) questions, I’d be grateful. Does changing the mode of a photo from grayscale to RGB create channels that are equal to the channels I would have gotten if I had scanned in RGB in the first place? Also, I’d appreciate learning from you what resolution you recommend scanning photos in, if they are scanned prints and separately if they are scanned slides. Your advice would be appreciated.

Thanks.

Pedro

"Mike Hyndman" <tell me yours and I’ll send > wrote in message

"Pedro" wrote in message

Thanks for the reply, Mike. With all of what you said, can I avoid rescanning by just changing the mode of the already scanned Jpeg files to 16 bit and RGB? I realize I need to change the format to Tif in order to get 16 bit. Or put another way, will the current scans give me the same channels and or 16 bit depth as if I had scanned to a Tiff file if all I do is change the mode to RGB and 16 bit via Photoshop?]

Pedro
If you have scanned and saved them as JPGs prior to manipulation. then you will have already lost some of the scanned data when you saved the file as a lossy JPG. When scanning, you need to extract every last ounce of information out of the scanned image (high res scan ) then save it in a lossless format, e.g., TIFF.
I tend to work with and restore old B & W images, sometimes "tinting" them or giving them an old sepia effect and 8bit RGB works perfectly well. These images, coming from the era when they were shot, would have had a much more limited colour palette anyway, (if at all) compared to what is available today.
Why do you need 16 bit? This is 281,474,976,710,656 colours, 8 bit is "only" 16.78 million colours.
If your final image size is quite small, (like for like?) you shouldn’t be unduly worried, I would just choose the Image mode required, 8 or 16 bit.(try it and see if you can see any difference) Old photos tend not to be the sharpest around in any case.

Lastly, I’d appreciate your advice on what resolution to scan prints and slides that I plan to restore. I have access to a separate film scanner for the slides.

I scan at the highest resolution (this differs according to "original" size) that my system memory will allow and is also dependant on what size I intend to print the finished file at. Transparencies need to be scanned at the highest possible setting if you intend to print higher than 10 x
8. It’s a "suck it and see" situation. 😉

Thanks again.

You’re very welcome, have fun!
Mike H

Pedro.
"Mike Hyndman" <tell me yours and I’ll send > wrote in message

"Pedro" wrote in message

I read the explanations about the above (which were very informative), but I had some more questions that I would be grateful for someone answering.

I am restoring some old B&W photos and am using PS CS2. I have scanned quite a few of the photos in Jpeg and in grayscale. In reading Katrin Eismann’s book on restoring, it is clear I should have scanned those old photos in Tiff to get 16 bit depth and in RGB to take advantage of the restoration techniques that use the RGB individual color channels. However, I would like to avoid rescanning, except where absolutely necessary.

If I change the mode of the scanned photos to RGB from grayscale in Photoshop, will the effect be much different than if I scanned first to RGB? Also, will changing the depth from 8 bit to 16 bit in Photoshop be much different than if I scanned the photos first in 16 bit?

Thank you in advance for any advice you can give me.

Pedro,

I do this a lot and I find (personally) that a high scan resolution has more of an effect than colour depth. Are you scanning an image in the scanner software, saving it as a file, then opening the image in PS or are you using the File>Import>(Scanner name) command in PS? If the latter, you will merely be importing a stream of pixels (the more the merrier) that hasn’t got a file type assigned to it, until you do a save. So in this scenario it would be the amount of pixels that you import that would be the important consideration. Once imported, you apply whatever colour space/depth/image mode you need to to achieve your ends.
If you are doing the former, then it would be better to save the file as TIFF as this format uses a lossless compression algorythm so no scanned data is lost.
I don’t see 16 bit as being an advantage and have yet to see any discernable difference in output quality on the size of image I work with. Also, you will be reducing the amount of filters, as not all will work in 16 bit.

HTH
MH