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Help needed to export client image for 24"x24" print

Forum|Forum|8 years ago
April 5, 2017
3 replies
3219 views

New to Lightroom/exporting using online month to month version. Delivering image file only to client so they can print 24"x 24" on matte paper. Library mode/Metadata, Dimensions are 3406x3406 cropped. Can I change to 7200x7200 (300dpi)? This would give me the correct measurement for desired print size, no? Exported file sizes are between 5-6MB, but it's my understanding that this is irrelevant bringing me back to dimensions.... During File export, Image Sizing seems to have an option for Dimensions, but checking Resize to fit seems to be a no no from research? Left confused...

Appreciate any step by step help.

Thank you!!

[Moderator note: title edited for clarity & brevity]

exprting dmensions

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Correct answer Per Berntsen

When you enlarge an image, the missing pixels will have to be invented when you export. This will reduce image quality - how much depends on how much you enlarge it.

In your case, you have a 3406 x 3406 image, containing roughly 12 million pixels.

The enlarged image will contain 7200 x 7200 pixels - 52 million pixels - which means that 40 million pixels will have to be invented - the majority of the image.

But chances are that such a large image doesn't need 300 ppi for printing, 180 might be enough, in which case you only need 4320 x 4320 pixels, or 18 million pixels, a relatively modest enlargement, and you may find the quality acceptable.

To do this, check Resize to fit, and enter 24" under Long edge, and 180 under Resolution.

For best results, use Output sharpening for print, try Standard.

And if you export as jpg, set quality to 100, or even better, export as Tiff, which does not use lossy compression.

Geoff the kiwi

Community Expert

I don't see the file/image posted here so no one knows what it looks like.

It is easily possible to print super large (read 2x3 metres) from a 6mp file ... viewing distance, position, use are all in the equation....

let's not over complicate this.....

bb7bAuthor

Participating Frequently

Per Berntsen, could you advise your suggested Resize to fit dimensions specifically for my photos 1,2, and 3? Step by Step?

How do I address the "Don't enlarge" option?

If it sounds like I'm asking you to do this for me, I am. I've learned so much and will no doubt continue my research, but need to get these images out and not trusting my novice calculations.

Again, these are my current cropped sizes all needing to result in a quality 24"x24" B&W matte print:

1. 3406x3406

2. 3058x3058

3. 2811x2811

Thanks in advance!

Per Berntsen

Community Expert

Since you want to enlarge the photos, Don't enlarge has to be unchecked. Checking this box prevents the image from being enlarged. I have created some examples to illustrate what happens when you enlarge an image, using your cropped dimensions.

I used the image below, a sharp 6000 x 4000 image.

First, I exported the whole image full size, with these export settings:

which resulted in this, viewed at 100% in Photoshop:

Then, I created three cropped versions, at 3406, 3058, and 2811 pixels, and exported them with these settings - enlarging them all to 24 inches, 180 ppi.

As you can see, the quality gets worse the more you enlarge. The 3406 image doesn't look too bad, but the 2811 image has in my view been enlarged too much. But this all depends on the nature of the image, your requirements, and the viewing distance.

I suggest that do these exports yourself, and view the images at 100% to evaluate them.

The best thing is obviously to avoid enlarging altogether.

bb7bAuthor

Participating Frequently

Thank you for the visual reference...I agree, not the quality I would like to see. This leads me to yet another question...

I am shooting with an entry level DSLR Canon Rebel T4i...lenses EF 17-40mm and a borrowed stock lens EFS 55-250. The client wanted a square crop so I had to crop almost half the shot as it was shot with the 17-40. Is my equipment and not having photoshop limiting my capabilities to accept jobs requesting large prints?

Per Berntsen

Correct answer

Community Expert

When you enlarge an image, the missing pixels will have to be invented when you export. This will reduce image quality - how much depends on how much you enlarge it.

In your case, you have a 3406 x 3406 image, containing roughly 12 million pixels.

The enlarged image will contain 7200 x 7200 pixels - 52 million pixels - which means that 40 million pixels will have to be invented - the majority of the image.

But chances are that such a large image doesn't need 300 ppi for printing, 180 might be enough, in which case you only need 4320 x 4320 pixels, or 18 million pixels, a relatively modest enlargement, and you may find the quality acceptable.

To do this, check Resize to fit, and enter 24" under Long edge, and 180 under Resolution.

For best results, use Output sharpening for print, try Standard.

And if you export as jpg, set quality to 100, or even better, export as Tiff, which does not use lossy compression.

bb7bAuthor

Participating Frequently

Thank you Per Berntsen! I appreciate your helpful explanation. Can you go into detail what "Resize to fit" does to the file? And why some people may choose not to check the box?

Per Berntsen

Community Expert

When Resize to fit is unchecked, the pixel dimensions of the image will not be changed on export - i.e. the exported image will have the same pixel dimensions as the original.

When Resize to fit is checked, the exported image can be made smaller than the original (you would do that if the image is going on the internet, or to make a small print), or it can be made larger.

Reducing the size of an image does not generally reduce quality, but increasing the size will reduce image quality, because missing pixels will have to be invented (interpolation).

It's important to understand that digital images do not have physical dimensions, they only have pixel dimensions.

The ppi (pixels per inch) number tells the printer how densely these pixels should be printed, and this determines the physical dimensions.

For instance, an image that is 3000 pixels wide will print 10 inches wide at 300 ppi, because 3000:300 = 10.

Lightroom does this math for you, even if physical dimensions are not a property of the image.

For on-screen viewing, ppi is irrelevant - the image will display according to its pixel dimensions.

You may also find this article useful: What is a digital image?

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