[Gimp-user] file extensions and when to use them
I usually shoot in RAW and convert with UFraw plugged in GIMP. Then I have a choice of extensions to use for saving the file produced. I presume that if I use .xcf there is no compression and if I use .jpg there will be some compression. When working on the file I assume it is best to save as .xcf and not to use .jpg until the picture is finalised. I would like to know how the contents of the .jpg file so formed compare with the contents of a .jpg saved directly on the camera. The reason I ask is because I would like to use PTLens to remove CA but it seems that the software will only work with .jpg. Norman ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] file extensions and when to use them
* norman [EMAIL PROTECTED] [03-21-08 13:06]: I usually shoot in RAW and convert with UFraw plugged in GIMP. Then I have a choice of extensions to use for saving the file produced. I presume that if I use .xcf there is no compression and if I use .jpg there will be some compression. When working on the file I assume it is best to save as .xcf and not to use .jpg until the picture is finalised. I would like to know how the contents of the .jpg file so formed compare with the contents of a .jpg saved directly on the camera. The reason I ask is because I would like to use PTLens to remove CA but it seems that the software will only work with .jpg. *compression* is not the problem as such. lossey compression is the problem, you *lose* some of the definition of your object/picture when you *save* it as jpg. jpg is a lossey compression scheme. If ptlens is your *only* choice, you have no choice except to perform that operation as the last operation. You will still have a minimum of two lossey saves. -- Patrick Shanahan Plainfield, Indiana, USAHOG # US1244711 http://wahoo.no-ip.org Photo Album: http://wahoo.no-ip.org/gallery2 Registered Linux User #207535@ http://counter.li.org ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] file extensions and when to use them
Norman, On Sat, Mar 22, 2008 at 10:48 AM, Patrick Shanahan [EMAIL PROTECTED] wrote: * norman [EMAIL PROTECTED] [03-21-08 13:06]: I usually shoot in RAW and convert with UFraw plugged in GIMP. Then I have a choice of extensions to use for saving the file produced. I presume that if I use .xcf there is no compression and if I use .jpg there will be some compression. When working on the file I assume it is best to save as .xcf and not to use .jpg until the picture is finalised. I would like to know how the contents of the .jpg file so formed compare with the contents of a .jpg saved directly on the camera. The reason I ask is because I would like to use PTLens to remove CA but it seems that the software will only work with .jpg. *compression* is not the problem as such. lossey compression is the problem, you *lose* some of the definition of your object/picture when you *save* it as jpg. jpg is a lossey compression scheme. If ptlens is your *only* choice, you have no choice except to perform that operation as the last operation. You will still have a minimum of two lossey saves. What Patrick has said is true. It's also true that you can save your jpeg with maximum quality in GIMP, and hopefully use a setting in PTLens to save the processed jpeg with maximum quality*.. Given an input picture of high resolution, the jpeg artifacts should remain near imperceptible. * if you can make PTLens use the same quantization tables as the input jpeg, that would give best quality. Another method that may work to minimize the effect of jpeg lossy compression is to scale the image up (no interpolation) before processing it, and scaling down afterwards. ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] file extensions and when to use them
Patrick Shanahan wrote: If ptlens is your *only* choice, you have no choice except to perform that operation as the last operation. You will still have a minimum of two lossey saves. ptlens is not the only choice. You could use Gimp. -- David Hodson -- this night wounds time ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
