Deleted
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Post by Deleted on Sept 7, 2018 21:21:06 GMT
This will mainly qualify for the classic stamps with few colors
Scanning has components of art, technical skill and T&T (not Thurn & Taxis but Trial & Testing) Assuming you have a dedicated scanner and reasonable software that allows for image type flexibility the choice is what image format? GIF, JPG, TIFF or PNG First of all thinking that the best way to achieve nice images is to scan say at 1200 DPI and then reduce the image to a suitable size is FALSE and a waste of time.
1200 - 4800 DPI is great for seeing fine details but slow and you still don't necessarily have a good image. If you want to immediately see fine details GET one of the many digital microscopes in the 20-50X range suited for this type of work.
For scanning images to a general website 300DPI is more than adequate if you have a decent scanner/software combination. So back to which image format? These were scanned and saved to their respective file formats WITHOUT any compression. A quick word on compression - yes you can reduce the file size with compression but you need to know that some types of compression result in no quality loss and others don't - too complicated for now. JPG 340Kb size
PNG 728Kb size - The TIFF was basically the same size but the TSF image host did not pick it up?
GIF 218 Kb size SO for images with few colors (IE your classics), there is very little quality difference but the PNG (and TIFF) uses a lot of space and although they may be suitable for certain color photographs and transparencies, IT IS JUST A WASTE OF SPACE FOR A FORUM IMAGE AND IT GREATLY INCREASES UPLOAD AND DOWNLOAD TIMES NOT TO MENTION THAT IMAGE SITES PAY FOR SPACE USED AND TRAFFIC SO THEY MAY EVENTUALLY EXPERIENCE HIGHER OPERATING COSTS. Another thought is that if you're stuck on PNG files use the lower size format PNG 8 instead of PNG 24
The GIF format is not widely used but it uses a color palette of 256 colors (in other words for the above, 256 shades of green) which for classic stamps is just fine
Anther reason to properly downsize your image - Many forums and image site want to preserve space as space used = $$. So they will casually compress or resize your images with notable quality loss. Photobucket was notorious for doing this and on previous posts I showed their before/after results.
SO is there another solution - YES if your scanner or software supports RAW scanning
RAW images are used by professional photographers as they reproduce the finest images. They are unprocessed images and result in the highest quality.
This is the RAW image (746Kb) and it reproduced the best quality and it was much truer to the actual image color. The PNG, TIFF, JPG GIF did not represent the original stamp color very well.
Size wise it was the same as the PNG or TIFF.
There is a notable difference between it and the others above - magnify the edge of the perforations (1200x) of the RAW and PNG/JPG and you will see why.
From there you can easily convert the RAW images to a JPG of a much lower size without any appreciable quality loss.
RAW to JPG with 80% compression size - 115Kb
RAW to JPG with 40% compression size - 80Kb
So provided the software/hardware is present, you can achieve high quality images with 1/5th-1/10th the size of most image formats.
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Admin
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Post by Admin on Sept 7, 2018 21:33:47 GMT
...The TIFF was basically the same size but the TSF image host did not pick it up?... The software used by the TSF Image Host only allows four image types: JPG, PNG, BMP and GIF. |
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tobben63
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What I collect: I collect to much, world wide!
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Post by tobben63 on Sept 8, 2018 2:04:15 GMT
Very informative. I only have a scanner combined with a cheep Samsung B&W laser printer with a not so impressive software. I need the printer and got no space for a dedicated scanner.
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Post by feebletodix on Sept 8, 2018 8:52:33 GMT
Just had a look at my software, it automatically saves as PNG and irritatingly will not allow it to be permanently changed so that has to be manually set each time.
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angore
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Post by angore on Sept 8, 2018 11:13:14 GMT
Many forums limit file size to around 200kB. This works for most web display purposes.
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Post by feebletodix on Sept 8, 2018 13:28:42 GMT
The first forum I visited had overlays set for 600dpi to aid with online perforation estimates, the second had a 1.4MB limit. Neither cared about file type only that the image would fit on a single screen (a few years ago before the photobucket site was bought out). On a 44" UHD TV the recent images which have been posted on the forum come up lovely and clear at about 30-35cm wide.  |
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renden
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Post by renden on May 3, 2019 12:26:16 GMT
Since I just purchased an EPSON dedicated flatbed scanner, V370 and that I reread this thread, one question for @falshung (Nelson): how do you do a RAW scan, as you recommend - I save my images in jpeg format - OK ? I agree with you that scanning at high resolution is a waste of time for the purpose of putting a stamp on the Forum
Thanks !
René
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brightonpete
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Post by brightonpete on May 3, 2019 13:04:14 GMT
Since I just purchased an EPSON dedicated flatbed scanner, V370 and that I reread this thread, one question for @falshung (Nelson): how do you do a RAW scan, as you recommend - I save my images in jpeg format - OK ? I agree with you that scanning at high resolution is a waste of time for the purpose of putting a stamp on the Forum Thanks ! René I don't think Nelson is around now. You can save in a better format. Anything is better than JPG (GIF, BMP). Use TIF, PNG, PSD... |
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renden
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Post by renden on May 3, 2019 13:59:21 GMT
brightonpeteThis is what Nelson wrote in his post, in this thread...... SO for images with few colors (IE your classics), there is very little quality difference but the PNG (and TIFF) uses a lot of space and although they may be suitable for certain color photographs and transparencies, IT IS JUST A WASTE OF SPACE FOR A FORUM IMAGE AND IT GREATLY INCREASES UPLOAD AND DOWNLOAD TIMES NOT TO MENTION THAT IMAGE SITES PAY FOR SPACE USED AND TRAFFIC SO THEY MAY EVENTUALLY EXPERIENCE HIGHER OPERATING COSTS. Another thought is that if you're stuck on PNG files use the lower size format PNG 8 instead of PNG 24 The GIF format is not widely used but it uses a color palette of 256 colors (in other words for the above, 256 shades of green) which for classic stamps is just fine Read more: thestampforum.boards.net/thread/5645/which-image-type?page=1#ixzz5ms01naPi
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khj
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Post by khj on May 3, 2019 15:05:23 GMT
The "RAW" scan is basically the bitmap scan (BMP). It takes up the most space, as it is completely uncompressed (which also means it is lossless).
Since hard drive storage isn't really an issue, I typically scan/keep a bitmap file. I'll crop the bitmap file as needed, and save that again in bitmap -- that serves as my "original". From that, I will image process (reduce, lighten/darken...) as needed and save in a compressed format such as jpg. I use the compressed file to upload.
I have a different take on "anything is better then jpg". Jpg is very convenient to work with, and intermediate to advanced graphics software will allow you to set the amount of compression. I think the problem is that many who try jpg make the mistake of manipulating their image in jpg while doing repeated saves. The compression is not lossless, so each time you make a save, you are recompressing and losing more image quality. Combined with the fact that most basic image software (including some scanner software) tends to set a high compression for jpg, you lose image quality quite quickly after a couple of saves (you might lose 25% on the initial scanning save alone!). That is why Nelson mentioned scanning to save a RAW (e.g., BMP) file first.
Intermediate/advanced image processing software (including some scanning software) allows you to set the jpg compression rate. For even better image quality, consider using 90% or higher when doing your final save for images that require very fine detail. I normally use the defaults (typically ~75%, depending on software) for most images I upload, but I only do one save. If you plan on making a series of changes/saves, you should work in BMP or TIFF (which is also lossless, but proprietary).
GIF tends to achieve smaller filesizes on grayscale or near mono-color images. But it's too much trouble for me to switch between using gif/jpg, so I just do my final saves in jpg.
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angore
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Post by angore on May 3, 2019 15:43:31 GMT
RAW is usually as captured by the camera or scanner's sensor with minimal processing. There may be processing to correct uneven response of sensor (color, noise, etc). For camera images, I usually work with raw because you have more flexibility. A JPG is a processed to get it into smaller image than the raw so image quality is less (not always noticeable). If you are not doing any post processing, saving to JPG It is not a good practice to edit jpgs repeatedly since image will degrade.
For scanning stamps, you need to scan at a higher dpi so the image is larger size otherwise you will get close to actual size rendering. It still can be saved in jpg to create a smaller image. For posting, I usually scan at 600dpi for regular stamps.
Epson can save in tiff or bmp. Now, when you tinker with the Epson settings like use auto you are telling Epson to process the image more than original image,
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