Image sizing problem in Lightroom classic cc

Peter123

Peter123

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Peter
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I have been asked to re-size a batch of images for a website so that they load quicker on a mobile.
1200 long side priority, 800,000 min. pixels.
I was also asked could 678 be the short side.
I don't normally fill in the short side when I export and have always left it blank without any problems (I know that it will vary depending on image)
So I tried and it didn't come out as expected (less than 800 for some) but when I try to revert to a blank in the export tab it now makes me input a figure.
is there any way I revert to blank on the short side when exporting.
Most of the images have been saved at about 16:9 but have all sorts of crops to achieve this aspect ratio,
 
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OK I've worked it out myself. I've re-set the export preferences.
Now, how to ensure they are min. 800,00 pixels. Any suggestions?
 
If the long side needs to be 1200 px then as long as your other dimension >667px, you'll be fine
 
If the images are cropped to 16:9 ratio then exporting with the long side at 1200 will give you a short side of 675. If they want them exactly 1200x678 then you need to crop them to 16:9.04

It would make your life easier if you cropped them all to that same ratio... in fact I cant see any other way
 
Well I’ve about 500 to do.
most are cropped 16:9 but a fair few aren’t.:(
Thanks to both for your help.
 
You can automate it. If you crop the first one to 16:9 then with that one still selected, select the rest, click on sync, click check none and then click on crop, aspect ratio and then syncronise.

It will make all of them 16:9 and as long as they weren't a drastically different crop they should be ok
 
OK I've hit another problem.
The re-size and sync has worked well but I am now being asked to make the kb's 30 - 50 max.
With over 800 images they are coming out at different sizes.
I've played with every box in LR export and find some will reduce OK but others the LR system wants as high as 120kb.
I'm saving at a resolution of 72 ppi (best for the net I'm told), all are 1200 x 670 dimensions, don't enlarge box is ticked, and I have set the megapixels at 1.0 which is the minimum LR will allow.

Is there any way to uniformly save all these at low kb (bearing in mind they need to be min. 1200 pixels on the long side and min. 800,00 pixels total)?

All are usable but this is about loading quickly onto iphone screens.

The images were all shot on a mixture of cameras i.e. D750, D500, Z7 and occasionally a Fuji X- series. I suspect the problem comes from how much I've cropped each image from the orginal.

So, if anyone can help please do.
 
There's a "limit file size" under File Preferences in the Export settings.
 
Harlequin565 said:
There's a "limit file size" under File Preferences in the Export settings.
Click to expand...

Thanks.
I complete this box and set it to (say) 50kb. But even though an image may have the same settings as others that save to less than 50kb, LR pops up saying that it could not create a jpeg and I need to increase the file size limit. The acceptable limit varies from image to image.

So, how do I overcome this and what is the reason?
 
I'm guessing there are some images that need a certain amount of pixels to comply with your px dimension requirement and by doing that, it would take the file size over your file size limit.

The only workaround I can think of is to export all the images at a max of 50kb (leave the px dimensions alone) then re-import them and export again with the px dimensions set. Bit of a convoluted mess but what you're trying to do is extremely specific.
 
Thanks I will give that a try.

Edit - tried and it doesn't work.
 
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In the image sizing box I unclicked resize to fit I chose megapixels, set it to 1 and then exported, but it lowers the dimensions below 1200 x 670.
I then went back into dimensions to maintain them. If I click on megapixels 1 comes up - not sure whether it is active.

I'm guessing this is all to do with the amount of cropping to the original image. Most are cropped, some a lot more than others.
 
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Clearly neither do I!
I expected that with all long and short dimensions the same I could save them all to the same kB.
The do not enlarge box is checked.
 
Yes that's what I do.
I've just tried a jpg already saved to 1200 x 680.
The lowest kb allowed is 110.
Some are OK at 50.
Is it the pixel density?

BTW. I appreciate your help on this.
 
[take with a pinch of salt as it's mainly guesswork based on my curiosity]

50k is really small. That's 1/20 of a megabyte...

Doing the maths...

Assuming 24bit colour (8bit red, green and blue per pixel) = 3 bytes, your 1200x800 (960,000 pixel) image would be 3 (bytes) x 960,000 (pixels) = 2.8Mb uncompressed. Then you need to cater for the compression that .jpeg slaps on that (and I'm now out of my depth with understanding) which the internet reckons is 10:1 at "acceptable" quality loss. So that's 200kb. What you're asking for here is a 40:1 compression ratio and I'm guessing Lightroom can't do it and give you what it thinks is a usable image..

A quick Google reveals a couple of people have had this problem and the answer has been...

"You are trying to export at the original dimensions of 3456 x 5184 px and limit the file size to 3000k. Lightroom is telling you it can't be done. You have to either decrease the dimensions or increase the file size."

Googling "Lightroom compression limit" will probably get you in the ballpark, or the error that it is kicking out.
 
thanks for your efforts.
This is all about small files loading quickly on smart phones. Image quality is not paramount as they are only displayed for a few hours.
I have edited this example in photoshop 2021 and using save to web I've set at 50kb using optimize to file size and it got this last one down to 78kb, which I think will be acceptable.
Tomorrow I will do some more work on this and look at what you suggest. I'll also have some feedback as to how it loaded and looked when used.
 
I don't understand either.
It works for some and not for others.
I use exactly the system you describe.
I've tested the same image with both tiff at large dimensions and the jpeg already saved to those dimensions.
In both cases LR needed 120kb to save. Optimising the file size in Photoshop maintained the dimensions and the file size went down to 78kb (I typed in 50kb and tried it a couple of times - same result).
I can play with individual images but I need to sync over 800.

when I captured these (over several years) the way I processed and saved them worked fine. I saved to 16:9 format and typed in 500kb - the system they used then downsized them no problem.
Now they have changed the parameters so I have this challenge.
 
The file size issue is to do with the complexity of the specific image, and the compression used.
Looking at it in it's simplest form, consider an image that has every pixel black, and one that is half black, and half white.
The pure black image will compress more because it is a 'simpler' image.
As the complexity continues to increase, the size it can be compressed to will increase - and LR is unable to compress every image you try down to the 50k limit you have set.
 
Thanks Jonathan.
Yes that's what it is.
I don't think there is a way around this.
I think I will try and sync them all at 50kb and see how many are left.

The other query is why I can go lower in Photoshop than LR?
 
j crossley said:
Can you upload one of the problem images to Dropbox or Google Drive. That way we might be able to shed some light on the issue.
Click to expand...

Not sure I will be allowed. They are very protective and have chased several who have ripped off some of these. Kindly they gave me half the proceeds!
 
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