DPI lost in translation

Swartzy

For some strange reason I can't seem to find where to change the import resolution in Lightroom.

Here's what's happening: Camera RAW is 350 dpi straight out of the camera..when I pull them in to DPP...all is well. When they are pulled into Lightroom, edited then sent over to Photoshop, the dpi is now at 240. I've looked in the PS preferrences, the Lightroom preferrences and am having fits. I don't want a program arbitrarily altering my dpi (even though it's about print size). Any help or suggestions? Thanks in advance.

Swartzy

Ok...I think I get it
Apparently the overall image has not been affected, simply the print size. The overall mgbyte size is not altered, simply the size, hence resolution. A smaller size warrants a higher dpi, a larger size, lower dpi.

claudermilk

Run a search, that metadata field is essentially useless. Feel free to ignore it (I do).

LiquidAir

Swartzy wrote:

Apparently the overall image has not been affected, simply the print size. The overall mgbyte size is not altered, simply the size, hence resolution. A smaller size warrants a higher dpi, a larger size, lower dpi.

Yep. Lightroom only modifies the pixels when you export or print. If you want to change the resolution in Lightroom, the place to do it is in the export dialog.

Swartzy

Still confused
Would someone be kind enough to explain this? In DPP the RAW files are 350 dpi.....when I export the file to PS...its still 350 dpi 7.something x 11. something. Follow me so far? When I pull the photos into LR, they automatically are at 240 dpi and when sending the file to PS they are slightly larger in size inch wise (8.871 X 13..something) but at 240 dpi.

Now, what am I missing? An almost 8 x 11 isn't that much smaller than an almost 9 x 13 to justify a difference in 110 dpi loss is it? Or am I completely missing it?

My concern is this: My old workflow of pulling RAW files into DPP, making adjustments then sending over to PS for the final edit has worked great...have sent many a shots to the lab for excellent prints...large ones!

The pixel amount remains the same but dpi is less coming from LR>

Now that LR arbitrarily decides to lower the dpi from intitial import (as I can't find a way to change that), even though the overall size of the file is now 8.871 x 13 something, am I going to loose quality in print? or...will the results be identical to the other workflow?

I don't want to get into having to resize images that come from LR. My brain hurts.

jfriend

Swartzy wrote:

Would someone be kind enough to explain this? In DPP the RAW files are 350 dpi.....when I export the file to PS...its still 350 dpi 7.something x 11. something. Follow me so far? When I pull the photos into LR, they automatically are at 240 dpi and when sending the file to PS they are slightly larger in size inch wise (8.871 X 13..something) but at 240 dpi.

Now, what am I missing? An almost 8 x 11 isn't that much smaller than an almost 9 x 13 to justify a difference in 110 dpi loss is it? Or am I completely missing it?

My concern is this: My old workflow of pulling RAW files into DPP, making adjustments then sending over to PS for the final edit has worked great...have sent many a shots to the lab for excellent prints...large ones!

The pixel amount remains the same but dpi is less coming from LR>

Now that LR arbitrarily decides to lower the dpi from intitial import (as I can't find a way to change that), even though the overall size of the file is now 8.871 x 13 something, am I going to loose quality in print? or...will the results be identical to the other workflow?

I don't want to get into having to resize images that come from LR. My brain hurts.

The only thing that really matters is the number of quality pixels you have. The dpi and the image dimensions (e.g. 8x10) are just labels applied to an image. Lightroom is preserving your pixel count (unless you mess with that in export) so that should be staying the same. As for the dimensions and dpi, those are just labels. If you wanted to label your image at a particular dimension (like 8x10) and the pixel count is not changing because you aren't resampling, then the ppi will just be calculated as #pixels/dimension=ppi.

If you wanted to specify the ppi, then the dimension would be calculated as dimension = #pixels/ppi.

No matter what the dimension and ppi are set to, the actual pixels of your image do not change and your prints should not be affected at all. The main thing the image dimensions are used for is figuring out how large to make a specific font size when you add text to your image. The main thing that ppi is used for is just to give you an idea how many ppi you would be giving the printer if you printed your image at the labeled size. Both are just guidelines.

When you tell your printer how big you want your image to be, neither the labeled size nor the ppi of your image are used at all. They are completely ignored and you should be able to ignore them too. Smugmug never users these values either. They only care how many pixels you have and what size print you asked for.

Swartzy

A most excellent explaination!
Thank you very much for clarifying this. Finally..finally...after how many years? I've not figured out this ppi thing...and now....epiphany!

You've explained it masterfully. What a great place this is. Again, thank you for taking the time, I truly appreciate it. Now the aspirin may remain in the cupboard

jdryan3

jfriend wrote:

If you wanted to label your image at a particular dimension (like 8x10) and the pixel count is not changing because you aren't resampling, then the ppi will just be calculated as #pixels/dimension=ppi.

If you wanted to specify the ppi, then the dimension would be calculated as dimension = #pixels/ppi.

I agree. Where I bolded the reply is where I see people get into trouble. The try and force the dpi AND the size - and there isn't enough data there. Then they try and print that rendering. As jfriend said further down, the printer will ignore that info, so there is really no reason to downsample/upsize unless you have storage issues, image control concerns, etc.

An image 600x900 pixels will be 2"x3" @ 300dpi (printing press), 4"x6" @ 150dpi (OK for inkjet prints; maybe a little thin) and 8" x12" @75dpi (close to your typical web size of 72dpi). Where people get in trouble is when they change the original to be 8"x12" AND 225dpi - the pixels just aren't there to produce quality output. Resampling can help in those cases.

But the bigger issue is why do you need 350dpi? I'll look for the thread or another link, but a printed large image can actually be OK at a much smaller dpi than a smaller image can. (SmugMug Help has something on this). It has to do with the typical viewing distance of those images. I always like to point out that billboards look fairly good - and look how big they are. Certainly not being printed at 300 or even 240 dpi.