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

[bb7b]

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]

[Per Berntsen · Accepted solution]

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.

[bb7b]

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]

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?

[JoeKostoss]

The algorithm used in Lightroom to increase an image by inventing pixels is excellent; a version of Genuine Fractals.  I have Increased a file that was originally 3756px x 2504px to 8640px x 5760px to make a 36 x 24 inch print at 240 ppi.  It looks fabulous when viewed from an ideal distance of about 7 feet away.

If you put your nose next to the large print, you can see the what Lightroom created, but, as a general rule of thumb, one should view a print from a distance equal to or greater than 2 times the diagonal.  A 4" x 6" print would ideally be viewed from about 14 inches; an 8 x 10 would be viewed from 25 inches.  My 36 x 24 print, when viewed from 7 feet away looks very sharp.  Your 24 x 24 print would ideal be viewed from about 5.6 feet, regardless if the ppi you chose from 300ppi, (Over kill) down to 180ppi as suggested by Per Berntsen or my suggestion of 240ppi.

[bb7b]

Thank you so much for this helpful info! So just to confirm, I have 3 images the client would like to print at 24"x24". A series that will be grouped together.

Currently (before making adjustments suggested above), my cropped images were saved as shown below. My understanding is that the prints would not be be of good quality at 24X24? I suppose I'm curious what I would get with this original export?

1. 3406x3406

2. 3058x3058

3. 2811x2811

Exported as:

JPEG

Quality 100

300 PPI

What I've learned, Adjustments need to be made for 4320 pixels on average with 180 DPI? I can't guarantee my client will be viewing from a far distance although I understand the logic!

[bb7b]

Also, I haven't mentioned that these images will print black and white. Are there any exceptions which I doubt? but worth mentioning...

[JoeKostoss]

If you print the images as is at 24" x 24", Photo 3 at 2811 x 2811 will print at 117 ppi.  That means that each individual pixel will be large, nearly 9 mils x 9 mils.  That is roughly 3 times the width of a human hair.  If you stand close ("Pixel Peep") to the printed photo, you will be able to actually see those pixels.  It will look "Pixelated".

bb7b  wrote

...What I've learned, Adjustments need to be made for 4320 pixels on average with 180 DPI? I can't guarantee my client will be viewing from a far distance although I understand the logic!

FYI, that is 180 PPI, not DPI.  DPI is dots per inch, or the number of droplets of ink a printer sprays our onto the paper.  Printers spray droplets at a much higher DPI, in the order of several thousand DPI.

Only photographers "Pixel Peep".  The distance viewed is limited by the length of their nose.

[bb7b]

haha, love "Pixel Peep" Joe! so true....

And yes, thanks for the correction of DPI...my intent. Thank you again for the explanation, I was concerned #3 would be pixalated due to size and appreciate the confirmation. Have learned so much and will follow through with "Per's" advise of Resize to fit option and adjustments.

[Geoff the kiwi]

Who is printing and on what material?? That makes a big difference... ask them what they need otherwise you are shooting in the dark!!

[bb7b]

Geoff the kiwi, I understand your point as well. Any thoughts on Mixpro? The client is leaning towards them for printing needs with option for a "true black and white paper with matte finish..."Geoff the kiwi, I understand your point as well. Any thoughts on Mixpro? The client is leaning towards them for printing needs with option for a "true black and white paper with matte finish..."

[bb7b]

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]

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.

[bb7b]

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]

Lightroom actually does a slightly better job of enlarging than Photoshop, so Photoshop wouldn't be of any help in that respect.

But it would help to have a camera with more pixels, your Canon has 18 megapixels, and 3456 pixels on the short side.

A 24 megapixel camera will usually have 4000 pixels on the short side, allowing you to print 22" at 180 ppi without enlarging, provided that you can fill the format, and don't need to crop.

A 36 megapixel camera will have around 4900 pixels on the short side, which will allow a 27" print at 180 ppi without enlarging.

I would reshoot this job if possible, making sure to fill the frame, so that cropping on the short side will be minimal.

Or even better, borrow a camera with a higher pixel count if you can. Your 17-40 lens can even be used with full format, but I think the 55-250 only covers the APS-C format, the format your camera is.

[Geoff the kiwi]

I have no idea about printing houses as I am from New Zealand but living in Uganda!!

But the wise move is to settle on the printer and style/paper then ask them what file formatting would be best. They should know their needs best ...

I am sure you will end up with a great result better than expected - let us know what you ended up with

Geoff Walker

Sent from my Phone

[Bob Somrak]

For trying to create enlargements with 24" in the short dimension   (24X36    24X24  etc) and using APC or even Full Frame DSLR's it not just about the camera and lens but the WHOLE photo process.

Here is a few:

Having the camera on a tripod and using mirror lockup and a remote release to eliminate shake.  (a big killer of quality)

Using the lens at its optimum f stop where it is sharpest if the photo allows it. 

Getting the focus spot on.  Using live view and manual focus if needed and the photo allows it.

Using lower ISO settings to eliminate noise.

Try to crop in camera so you don't have to waste pixels  (you don't have many to start with.)

As far as cameras are concerned, if you want to do large prints than a full frame sensor and with lots of pixels is a must.  Also sharp lenses are a must.

If you want to use your present camera and lenses for large photos and if the subject allows it (no movement) than you can always zoom in from the same position and take a 3X2 or a 6X4 or more multi column/row panorama off a tripod and stitch the photos in Lightroom.  The perspective of the photo will be the same as the single photo if you shoot from the same position.  Using this technique will let you print HUGE photos at high resolution.

[bb7b]

Thanks for all the feedback. I'm learning so much. Unfortunately, I'm unable to reshoot the project because the season was snowy ideal and now we are into spring. And cropping in camera was a bit of a challenge due to shooting moving trains (danger, danger) which had me zooming and using glass on a lens that was noticeably lower quality than some to avoid being too close for comfort. All food for thought as I move forward!

Knowing now that my export size will not give high quality prints at 24x24, as a professional, should I delicately suggest a smaller print size and compensate the desired 24x24 total size with matte and frame, therefore, hoping to  reduce image size to a 19" or 20" square print to enhance quality?

Promise this thread will be checked "correct answer" soon, just gathering my best options to move forward with what I have! appreciate all the input!

[Bob Somrak]

If you have CC than export a TIFF to Photoshop at the original size and then use Image Size to upsize/resample in Photoshop using the NEW Preserve Details resample method.  It works VERY well on some photos.  This might work for your project.

[JoeKostoss]

You are over thinking this project!  The quality degrades slightly, but you do not see it when viewed from a proper distance.  You cannot truly determine the quality of a large print by viewing the image at 100% on a computer screen; that is pixel peeping at its worst.  Pick your image, enlarge it on export and get a print made.  It is the only true test in this situation.  If your client wants a 24 x24, she is obviously going to hang it on a wall to be viewed at a reasonable distance.  I predict that she will be happy.

If, in the future, you plan to continue producing large prints, then do follow the advice of others here and upgrade the camera, but for now, it is what it is.

[Geoff the kiwi]

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.....