Help with batch resizing images

[Timothy Knox]

Quick context: I am a photographer who often shoots both portrait and landscape orientation in the same session. I use GC to convert the images from RAW, and to downscale them. Ideally, I'd like to scale all images down to (for example) 816x544 or 544x816. However, when last I tried choosing a pixel size (such as 816), I'd wind up with some images that were 816x544 and some that were 1224x816. What I really want to say is, "Make the longest side 816 pixels, regardless of orientation, and scale the shorter side to match." Unfortunately, I can't seem to manage that. The best I've found is to take a percentage, but it doesn't seem to honor fractional percentages, so I wind up with small images that are not fully composed of 8x8 blocks, and therefore cannot be losslessly rotated (for example). Is there something I am missing, or just not seeing? Many thanks to you, for your assistance. And mondo thanks to Thorsten for my favourite batch processing image application EVER! -- Timothy Knox <mailto:tdk@thelbane.com> I like to say that in the old days, if you reinvented the wheel, you would get your wrist slapped for not reading. But nowadays people are reinventing the flat tire. I'd personally be happy if they reinvented the wheel, because at least we'd be moving forward. -- Alan Kay

[thorstenlemke]

Dear Timothy,you can do this really simple with a  batch in convert & modify for a large set of files.Use the if / else / continue for this.Did you try it? I can make a short tutorial movie if a more detailed description is required.ThorstenOn 23.01.2014, at 02:02, Timothy Knox <tdk@thelbane.com> wrote: Quick context: I am a photographer who often shoots both portrait andlandscape orientation in the same session. I use GC to convert theimages from RAW, and to downscale them. Ideally, I'd like to scale allimages down to (for example) 816x544 or 544x816. However, when last Itried choosing a pixel size (such as 816), I'd wind up with some imagesthat were 816x544 and some that were 1224x816.What I really want to say is, "Make the longest side 816 pixels,regardless of orientation, and scale the shorter side to match."Unfortunately, I can't seem to manage that. The best I've found is totake a percentage, but it doesn't seem to honor fractional percentages,so I wind up with small images that are not fully composed of 8x8blocks, and therefore cannot be losslessly rotated (for example).Is there something I am missing, or just not seeing? Many thanks to you,for your assistance. And mondo thanks to Thorsten for my favourite batchprocessing image application EVER! -- Timothy Knox <mailto:tdk@thelbane.com>

[Carl von Einem]

Timothy Knox schrieb am 23.01.14 02:02: > Quick context: I am a photographer who often shoots both portrait and > landscape orientation in the same session. I use GC to convert the > images from RAW, and to downscale them. Ideally, I'd like to scale all > images down to (for example) 816x544 or 544x816. However, when last I > tried choosing a pixel size (such as 816), I'd wind up with some images > that were 816x544 and some that were 1224x816. > > What I really want to say is, "Make the longest side 816 pixels, > regardless of orientation, and scale the shorter side to match." ++ I'd add something else to the wish list: if not already implemented, downsizing to thumbnails should have an option to downscale in 50% steps until the desired end format is reached. This helps preventing artefacts like oversharpening / aliasing, depending on interpolators. Carl > Unfortunately, I can't seem to manage that. The best I've found is to > take a percentage, but it doesn't seem to honor fractional percentages, > so I wind up with small images that are not fully composed of 8x8 > blocks, and therefore cannot be losslessly rotated (for example). > > Is there something I am missing, or just not seeing? Many thanks to you, > for your assistance. And mondo thanks to Thorsten for my favourite batch > processing image application EVER! >

[Timothy Knox]

Somewhere on Shadow Earth, at Thu, Jan 23, 2014 at 09:04:59AM +0100, Thorsten Lemke wrote: > Dear Timothy, > > you can do this really simple with a batch in convert & modify for a large set of files. > Use the if / else / continue for this. > Did you try it? I can make a short tutorial movie if a more detailed description is required. Okay, I've created a batch like that, that I will test out this evening. By the bye, is there documentation on the batch creation stuff? I groveled the Hagen manual and didn't see anything about it. Some of the batch items are obvious, but (for example) I would never have looked at the if/else/continue batch items without the pointer from you. I ask because some people have suggested I watermark my images (which I have refrained, up to this point, from doing). That seems a great use for batches, but batch documentation would help. -- Timothy Knox <mailto:tdk@thelbane.com> I like to say that in the old days, if you reinvented the wheel, you would get your wrist slapped for not reading. But nowadays people are reinventing the flat tire. I'd personally be happy if they reinvented the wheel, because at least we'd be moving forward. -- Alan Kay

[Marino Pascal]

You need the batch step "Max Size" Enter width: 816 Height:544 or even both at 816 check the boxes "invert dimensions for vertical images" and "Proportional" You'll get the longest side at 816. Marino On 1/22/14, 5:02 PM, Timothy Knox wrote: > Quick context: I am a photographer who often shoots both portrait and > landscape orientation in the same session. I use GC to convert the > images from RAW, and to downscale them. Ideally, I'd like to scale all > images down to (for example) 816x544 or 544x816. However, when last I > tried choosing a pixel size (such as 816), I'd wind up with some images > that were 816x544 and some that were 1224x816. > > What I really want to say is, "Make the longest side 816 pixels, > regardless of orientation, and scale the shorter side to match." > Unfortunately, I can't seem to manage that. The best I've found is to > take a percentage, but it doesn't seem to honor fractional percentages, > so I wind up with small images that are not fully composed of 8x8 > blocks, and therefore cannot be losslessly rotated (for example). > > Is there something I am missing, or just not seeing? Many thanks to you, > for your assistance. And mondo thanks to Thorsten for my favourite batch > processing image application EVER! >