|
Best Porn Sites | Live Sex | Register | FAQ | Members List | Calendar |
|
Thread Tools | Display Modes |
August 7th, 2009, 05:01 PM | #1 |
Former Staff
Join Date: Aug 2008
Location: Germany - Tripping the Rift
Posts: 1,427
Thanks: 16,756
Thanked 39,591 Times in 1,329 Posts
|
How to convert scans to reasonable size?
First my environment:
Hardware: Epson Perfection V200 Photo scanner Software: xsane-0.995 (Linux) I scan magazines at 300dpi with this environment, which produces PNM files which are about 25MB (2544x3509 pixel, depth 24). Of course I can't (or am not willing) upload these images directly to an image hoster. Therefore I currently convert the images with the convert program from ImageMagick: convert -resize '1680x1680>' infile outfile.jpg; This produces images with a maximum side length of 1680 pixels, the image size is about 300 KB. My question: Is there a better way to compress the images to a reasonable size?
__________________
PM me if my uploads are no longer available, I will re-upload them |
The Following 4 Users Say Thank You to svga For This Useful Post: |
|
August 7th, 2009, 06:31 PM | #2 |
R.I.P.
Join Date: Nov 2005
Location: Gone But Not Forgotten
Posts: 6,562
Thanks: 37,001
Thanked 77,388 Times in 5,393 Posts
|
I always batch-convert with GraphicConverter
PICT 32 bit -> jpeg
__________________
We got to let love rule. Last edited by Xxphd; August 8th, 2009 at 06:03 PM.. Reason: PICT |
The Following 5 Users Say Thank You to Xxphd For This Useful Post: |
August 7th, 2009, 07:03 PM | #3 |
Former Staff
Join Date: Aug 2008
Location: Germany - Tripping the Rift
Posts: 1,427
Thanks: 16,756
Thanked 39,591 Times in 1,329 Posts
|
Thanks for the response, butI have to rephrase my question: Is there a better way to get a better quality/image size (in bytes) ratio?
One example: I've converted the same scan with two different options to approximately the same size (380 kB): 1st Conversion: convert -resize '1680x1680>' page26.pnm page26-1680x1680.jpg (uses standard compression 85): 2nd Conversion: convert -quality 27 page26.pnm page26-q27.jpg (this sets the "JPEG compression" to 27 without changing the image size): Which one is better? Of course proposals for other programs which produce better results are welcome
__________________
PM me if my uploads are no longer available, I will re-upload them |
The Following 4 Users Say Thank You to svga For This Useful Post: |
August 8th, 2009, 03:09 PM | #4 |
Ups, i did it again
Join Date: Jan 2008
Posts: 2,305
Thanks: 6,077
Thanked 23,964 Times in 2,082 Posts
|
Panorama : resize / resample
left origin 95%, middle resize + zoom , right resample + zoom. ( irfanview ) The resample function in Irfanview softens during the resample and reduces the filesize. Panorama: jpg compression from left to right: 100%, 501KB 60%, 69KB 95%, 302KB 85%, 156KB It can be useful to save with high compression values ( 85%+ ) if the pic contains reflexions ( metal, fingernails, hair, ... ). Lower compression values decreases the depth effect due to lower brilliance.
__________________
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. . To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. . To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. . To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. |
The Following 5 Users Say Thank You to icu For This Useful Post: |
August 8th, 2009, 04:32 PM | #5 | |
Sourcer of Smut
Join Date: Aug 2007
Posts: 8,829
Thanks: 83,609
Thanked 341,654 Times in 8,422 Posts
|
Quote:
I don't know about Linux, but I use Irfanview myself. IMO it produces very good results with the quality setting at 80%.
__________________
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. Feel free to post my scans to the relevant model threads, but do give credit |
|
The Following 5 Users Say Thank You to Jism Jim For This Useful Post: |
August 8th, 2009, 04:43 PM | #6 |
Former Staff
Join Date: Aug 2008
Location: Germany - Tripping the Rift
Posts: 1,427
Thanks: 16,756
Thanked 39,591 Times in 1,329 Posts
|
No, the software itself can only produce PNM, but the formats are similar and I can convert to BMP with another tool without any loss of information.
__________________
PM me if my uploads are no longer available, I will re-upload them |
The Following 4 Users Say Thank You to svga For This Useful Post: |
August 8th, 2009, 05:22 PM | #7 |
R.I.P.
Join Date: Nov 2005
Location: Gone But Not Forgotten
Posts: 6,562
Thanks: 37,001
Thanked 77,388 Times in 5,393 Posts
|
25MB
producing a BMP or PICT will reduce the size to about 50% or even less of that I guess
__________________
We got to let love rule. |
The Following 4 Users Say Thank You to Xxphd For This Useful Post: |
August 8th, 2009, 06:16 PM | #8 | |
Former Staff
Join Date: Aug 2008
Location: Germany - Tripping the Rift
Posts: 1,427
Thanks: 16,756
Thanked 39,591 Times in 1,329 Posts
|
Quote:
Code:
> convert page26.pnm page26.bmp # converts PNM to BMP (lossless) > ls -l -rw-r----- 1 anon anon 26781040 Jun 26 23:43 page26.pnm -rw-r--r-- 1 anon anon 26780742 Aug 8 18:41 page26.bmp PNM and BMP are almost the same formats, they store for every pixel the full information (e..g. 24 bits RGB value or 8 bit grey value).
__________________
PM me if my uploads are no longer available, I will re-upload them |
|
The Following 5 Users Say Thank You to svga For This Useful Post: |
August 8th, 2009, 08:33 PM | #9 |
Veteran Member
Join Date: Aug 2007
Posts: 566
Thanks: 192
Thanked 12,244 Times in 432 Posts
|
Quote:
The first picture. Why? Because the second picture has too many JPEG artifacts.(the Quality=27 is too low) There is a problem here, the first picture's size is 1218x1680 (resized 50%), the second picture's size is 2544x3509. It's not easy to compare them when they have different sizes. Is there a better way to get a better quality/image size (in bytes) ratio? No. If you want good quality you pay with a bigger file size. The JPEG compression is lossy, you can use it with Quality setting between 70-100, 85 is a good compromise. Some HQ (big sizes) examples: 1. 200dpi descreen on - 600kB 3. 300dpi descreen off, edited - 1MB 5. 300dpi descreen on, edited - 1MB It's interesting that the 300dpi pic with descreen ON has a little moire, and with descreen OFF no moire. Tuffy Last edited by tuffy; August 8th, 2009 at 09:35 PM.. Reason: added some pics |
The Following 7 Users Say Thank You to tuffy For This Useful Post: |
March 15th, 2012, 11:20 AM | #10 |
paludicolous paravant
Join Date: Sep 2005
Location: Perfidious Albion
Posts: 26,735
Thanks: 75,664
Thanked 745,404 Times in 26,855 Posts
|
Back in the days when I was fiddling with these options, my rule of thumb was: scan with high resolution, reduce afterwards - although I left the reduction to a picture editor (PaintShop Pro), not the scanning software. Though this may have also been influenced by the tiny little issue that my first scanners didn't support picture reduction.
Anyway, that strategy that seemed to help with Moire patterns. When I got Moire with scanning at 300dpi I moved to 500pdi or even 1000dpi, creating a monster-sized file, and then let the picture editor do its magic afterwards. |
The Following 10 Users Say Thank You to beutelwolf For This Useful Post: |
|
|