How to Determine: Maximum Photo Print Size
– Digital Camera Megapixels (Calculator)
Updated – April 21, 2019
A word about digital photo printing and print service providers:
We can produce photo enlargements listed below with original image quality photo prints because of the highly advanced digital photo processing and photo enlargement software systems we utilize for pre-print image preparation.
We take the business of digital imaging and printing seriously, utilizing the latest state-of-the-art software and hardware systems to produce the finest quality photo enlargements available. This is all we do, and we take no shortcuts or spare any expense in providing high quality professional digital photo printing services.
You can’t expect the same high-quality digital photo printing results from other digital print service providers who may use only basic processing software and print systems to limit expenses and save time.
We stand behind our claims with a 100% customer satisfaction guarantee on all photo enlargements and digital photo printing orders.
– Image Pixels (Calculator)
– Using Photoshop
Determining what photo enlargement sizes a digital photo will produce is fairly easy. If you have a version of Photoshop or another image editing application with similar features, it is very easy to figure out photo enlargement print sizes. If you don’t have an image editing application, all you need to know is either the actual size of the existing original digital photo in inches, or the pixel dimensions of the digital photo.
Determining photo enlargement printing sizes with Photoshop:
All you need to do is open the original digital photo in Photoshop.
Go to the “Image Size” window.
For Photoshop CS versions – click image > image size
For Photoshop Elements versions – click image > resize > image size (may vary)
Note the Document Size section with width / height / resolution fields.
Make sure “constrain proportions” is checked.
Select (blue out) either width or height and enter any value you are considering for photo enlargement print size in inches.
The software will give you the corresponding dimension for an overall enlargement size.
IMPORTANT – when done, “Cancel” image size window to not apply changes.
Determining photo enlargement printing sizes knowing photo size in inches or pixels:
For this exercise we will use a digital photo with the following default sizes –
size in inches – 12 x 16
pixel dimensions – 2736 x 3648
Simply divide the larger number by the smaller number, either inches or pixels, for a ratio value. With the above example the value is 1.33.
Say you want an enlargement 30″ on the short side of the photo.
Multiply 30″ by 1.33 = 40″ (round up)
Overall photo enlargement size = 30 x 40.
Say you want an enlargement 24″ on the long side of the photo.
Divide 24″ by 1.33 = 18″
Overall photo enlargement size = 18 x 24.
This method of figuring overall photo enlargement print sizes is not precise due to the fact of rounding off numbers for ratio values and print sizes, but it will give you a very close estimate of your digital photo’s enlargement sizes.
How Photo Enlargements are Produced from Digital Photos
What you need to produce digital photo enlargements:
Enlarging and printing digital photos is all about the resolution, or pixel dimensions of the digital photo. The higher the resolution of the original digital photo, the larger the photo can be printed and still maintain the same image quality of the original digital photo.
Of course, there are a number of methods than can be used to increase the pixel dimensions of any digital photo to build resolution, but for the highest quality results, very advanced, professional software applications need to be used. The enlargement results from professional applications will yield image quality that is precisely the same as the original digital photo.
On the other hand, any digital image will have enlargement limits based on the original image resolution and even these advanced applications will have their processing limits. These limits will be explained further below.
What you really need for printing digital images is a final image file processed to it’s target print size with a resolution of at least 300 pixels per inch (ppi). Why 300ppi? This value is based on what the human eye can detect. At 300ppi, the human eye can’t detect the image pixel lines where you would have what is called a pixelated image. At resolutions lower, the pixel lines may become evident, and the lower this value is, the more evident the pixel lines will be.Example of a pixelated photo –
How the resolution of a digital photo is increased:
As mentioned, there are many ways to increase the resolution of a digital photo, meaning a great many different software applications, and some do a much better job than others. The basic principal of building resolution involves increasing the number of image pixels by averaging the actual image data and colors and applying this processed image data to the newly added pixels to duplicate or build the image into the new pixels. But as you can imagine, this building process may not yield an exact duplicate when applying the image data, and the greater the pixel percentage increase, the more this building inaccuracy will be visible. Very large percentage increases will greatly degrade the original photo quality.
Standard, over the counter type applications like Photoshop can do a pretty good job of building image resolution up to a certain point. There are methods of building resolution using percentage “steps” and this process usually yields a little better quality. As a general rule of thumb, with any system used for photo enlargements, you should keep the enlargement percentage at a maximum of 400% (4Xs) of the original resolution. This means either the image actual size in inches or the image pixels per inch. This can be a bit of a stretch for many standard image editing applications if you want original photo quality, but usually for sure, at percentages over 400% you will notice obvious degrading of the original photo quality.
Using Photoshop, the example below is building the photo resolution from a low 1024×768 pixels at a target print size of 10.667×8 @ 96ppi, to a printable resolution of 300ppi. To print this image at 300ppi you need to increase the resolution to 300ppi. How much of an enlargement percentage would this be? Simply divide the 96ppi into 300ppi and you get 3.125 times or 313%. This is a larger increase, but considering the smaller print size of 10.667×8, the loss of image quality may not be too noticeable.
To make the resolution increase, be sure both check mark fields are checked, constrain proportions – to keep the photo aspect ratio the same, and resample image – this means the software will build the resolution, and apply a value of 300 in the resolution filed. When you click OK, the photo will be resampled and you will have a printable photo at 300ppi at a size of 10.667×8. Note that the pixel dimensions have gone from 1024×768 in the original photo to 3200×2400 in the processed photo. This photo will not be pixelated when printied.
How professional quality photo enlargements are produced from digital photos:
In professional photo enlargement printing, the critical issue is making enlargements that will print with absolute original photo quality, and also creating very large print sizes. To produce very large prints usually requires processing the photo through a few steps using different professional grade photo processing applications, and still maintaining the rules of digital enlargement and printing. This means keeping any step in the enlargement process under the max recommended 400% resolution boost, and producing a final print resolution of 300ppi at the target print size.
The professional processing applications we use are cutting edge, and will produce photo enlargements that are much higher quality that typical image editing applications.
The example below is a project where the client wants a final wall size print of a digital photo sized to 36″w x 40″h for their clubhouse wall. The original digital photo has pixel dimensions of 2205×2448 which at a print resolution of 300ppi would produce a print size of 7.35w x 8.16h.
The first step in the enlargement process is to size the photo in Photoshop as seen in the example below. First we “uncheck” resample so the software does not resample or alter the original pixels values, and enter the target print height of 40″. This makes the photo width 36.029 at a resolution of 61.2ppi. This resolution needs to be increased to at least 300ppi to avoid having a print that is pixelated.
The second step in the enlargement is to process this file through an intermediate application that uses sophisticated fractal technologies to build the resolution to 120ppi at the target print size of 36.029w x 40. This will be an enlargement percentage of about 196%, well within the digital enlargement percentage limits to maintain original photo quality. The resulting photo file is sized to the required 36w x 40h print at a resolution of 120ppi.
The third and last step in the photo enlargement and printing process is to run the photo file through our highly advanced Raster Image Processing software (RIP). This software is the most important part of the overall enlargement process. The application will take this file, and through a patented process, builds the image resolution to a printing resolution of 360ppi before sending to the printer for output. This resolution build is 300%, also well within the digital enlargement guidelines. The resulting photo will print with precisely the same image quality as the original photo file had before any digital enlargement processing. We guarantee it!
– Using Photo Pixel Dimensions (Mathematical Equations)
The highly advanced and sophisticated printing systems software we use is taken
into consideration when formulating the method for determining max print sizes
possible from digital photos described below. Not all print service providers will be
able to match the results outlined since lesser quality print systems may be employed.
The photo pixel dimensions can usually be found by viewing the photo’s dimensions,
document size or properties. The pixel dimensions will be (a number) x (a number).
Example – 3888×2592
Once you know the pixel dimensions of your digital photo, all you need to do is
divide each dimension by 60 to determine the max print size in inches.
The calculations below are for determining a print size “range”.
Print sizes a little smaller, larger or even sizes will yield the same
print quality results.
Digital photo pixels dimensions – 3888 x 2592
3888 divided by 60 = 64.8 inches
2592 divided by 60 = 43.2 inches
Max recommended print size to print with original photo quality = 43.2 inches x 64.8 inches
Digital photo pixels dimensions – 2816 x 2112
2816 divided by 60 = 46.9 inches
2112 divided by 60 = 35.2 inches
Max recommended print size to print with original photo quality = 35.2 inches x 46.9 inches
Digital photo pixels dimensions – 1600 x 1200
1600 divided by 60 = 26.67 inches
1200 divided by 60 = 20 inches
Max recommended print size to print with original photo quality = 20 inches x 26.67 inches
This factor of 60 is actually a somewhat conservation value.
For digital photos of lower original pixel dimensions, about 2000 or less,
the factor or 60 is a good number to use.
For digital photos of higher original pixel dimensions, a factor of 50 or
55 could be used to determine max print sizes with the same quality results.
– Using Pixel Dimensions of the digital Photo and Aspect Ratio (Mathematical Equations)
The first step is to determine the image aspect ratio factor.
Simply divide the larger number by the smaller number to get a factor.
Example – 3888 divided by 2592 = 1.5 (image aspect ratio factor)
The next step is to consider a size you may want for either the short side
or long side of the photo.
If using the photo short side considering a size of 20 inches, just multiply this 20 inches
by the aspect ratio factor to determine the long side dimension.
If using the photo long side considering a size of 30 inches, just divide this 30 inches
by the aspect ratio factor to determine the short side dimension.
Examples of determining print sizes:
Digital photo pixel dimensions – 3888 x 2592
3888 divided by 2592 – Aspect ratio factor = 1.5
Considering a photo short side of 22 inches
22 inches multiplied by 1.5 = 33 inches
Overall print size = 22 inches x 33 inches
Considering a photo long side of 45 inches
45 inches divided by 1.5 = 30 inches
Overall print size = 30 inches x 45 inches
Digital photo pixel dimensions – 2816 x 2112
2816 divided by 2112 – Aspect ratio factor = 1.3333
Considering a photo short side of 18 inches
18 inches multiplied by 1.3333 = 24 inches (rounded to even dimension)
Overall print size = 18 inches x 24 inches
Considering a photo long side of 40 inches
40 inches divided by 1.3333 = 30 inches (rounded to even dimension)
Overall print size = 30 inches x 40 inches
Digital photo pixel dimensions – 3648 x 2046
3648 divided by 2046 – Aspect ratio factor = 1.783
Considering a photo short side of 28 inches
28 inches multiplied by 1.783 = 50 inches (rounded to even dimension)
Overal print size = 28 inches x 50 inches
Considering a photo long side of 32 inches
32 inches divided by 1.783 = 18 inches (rounded to even dimension)
Overall print size = 18 inches x 32 inches
With this simple method of determining print sizes for photo enlargements
using only the pixel dimensions of a digital photo, you can see what the
best prints sizes would be for your digital photos before selecting a size to order.
Advanced Photo Enlargement Processing for Digital Photos
How to produce very large print sizes with original image quality.
I have specialized in the processing and printing of digital photographs since 1997, and since 1999, have fine tuned that specialty to wide format digital photo printing. I must say, the technical advancements in digital cameras, digital image processing software and digital photo printing systems is absolutely amazing. In the past couple years, these technical advancements have taken leaps and bounds in print output capabilities.
Most individuals who have ventured into the world of digital photography in recent years, have a somewhat working knowledge of computers. They usually know how to get their latest photos from the storage card to their computer’s hard drive, and printed out on their desktop printer. Beyond that, well who cares as long as the photo prints look OK.
Many of these individuals have even gone so far as to delve into the subject a little deeper, and have read or heard about the resolution needed for good quality prints, a bit about file types, and even touched base with a version of Adobe Photoshop to process and enhance their works of art. This is all fine and dandy, but the problem that arises is that most of the knowledge they seem to collect in their search, is either outdated or dished out by those who sound like they know more than they actually do.
While it is true that you need a certain level of image file resolution to produce a fine quality photo print, how that level of resolution is achieved is another matter. Digital photo printing should be done with an image file that is at 200 to 300 dpi minimum, (actual term would be ppi for an input file, or pixels per inch). As important as the digital photo’s resolution is to achieve this resolution and print output size without resampling the original digital photo file to produce this resolution and print size. The absolute finest quality photo prints will be produced with the unresampled, original photo file.
To produce the larger print sizes now available on the affordable medium format digital photo printers, requires photo enlargement techniques. Most people simply open the original photo file in their version of Photoshop, and resize the file by entering the width and height dimensions, resolution dpi they want, leave the resample option checked and click the OK thinking all is just great. This will resample the photo file and degrade the original image quality. Photoshop uses a simple bicubic resampling method to resize the file. This method actually recreates and artificially produces new pixels for a higher image resolution and larger print size. This is the action that degrades the original image.
The Photoshop resampling will have to work if that’s all you’ve got. If your photo enlargement is not too big, the degrading of the image may not be too noticeable. If you require photo enlargements much larger, or prints in the range of 16×20 and larger, simple file resampling will not produce quality results. That is why you hear all over the Web that very large print sizes are just not possible, even from the newer high resolution digital cameras. NOT SO! I print and ship photo enlargements as large as 40×60 from 6 megapixel cameras and guarantee customer’s satisfaction. Have never had one returned!
To achieve high quality photo enlargement of digital photos requires a slight shift in processing thinking and a certain file handling methodology. You will also need to purchase additional digital processing software, besides your image editing application such as Photoshop. One application is a Photoshop plug-in utilizing fractal technology for image resolution boosting called Genuine Fractals. The second application, and most important, is a very high quality RIP software, or “Raster Image Processing” program that will reprocess input files before printing. RIP software is available, and highly recommended, for use with all medium format and large format digital printers where photo enlargement is the rule of thumb. Most quality RIP software applications today also include complete color management features, along with many other amazing editing and enhancement features.
Instead of preparing your digital photo for printing using Photoshop, you will only use this program to set up the file for photo enlargement and perform some sizing and cropping functions, and any image enhancements. Any required photo enlargement and image resolution building will be performed with Genuine Fractals. Digital processing to a proper output resolution will be done with the RIP software, which does a much, much better job of resampling the photo file than Photoshop. There are some enhancing functions that should not be performed on the image file until after the photo enlargement is at target print size. Read more photo enlargement tips here.
The best way to describe this advanced photo enlargement methodology is to walk through an example photo enlargement using a standard high resolution digital camera with a set large format target print size. For this example I will use a Canon 6.3 megapixel digital camera format with a 3072×2048 pixel dimension and a target print size of 30×40. This target print size will require photo enlargement and photo cropping.
Please note that the RIP software I will be using in this example will reprocess the final set up file to a resolution of 360 dpi before sending to the printer. It is best to use a set up dpi that is an even variable of the final reprocessed dpi. The lowest set up resolution I use for large format photo enlargement is 90 dpi. The key to the finest quality photo enlargements is to never resample the file in Photoshop.
Using Photoshop CS and photo in landscape orientation:
Start by opening the original photo file in Photoshop CS then:
Click image > image size
uncheck resample and enter “90” in the resolution field.
Produces an image: width 34.133 in. x height 22.756 in. at 90 ppi.- OK
Save in Genuine Fractals file format – encoding lossless.
Open the same file in the Genuine Fractals format.
You will note the same image specifics from the Photoshop sizing.
For the width and height fields select “inches” and enter: height- 30 and width- will automatically be 45. For width and height fields re-select “percentage” and you will see a photo enlargement of 131.836 % is required for this print size at 90 ppi. – Click OK
Please note that Genuine Fractals states photo enlargements up to 400% are possible, but experience has taught me that to maintain original image quality, it is usually best to keep this photo enlargement percentage within a maximum of about 225%. The quality of the photo enlargement depends on the pixel density of the original file.
Resave this processed file in a Photoshop format (.psd) or .tif format.
Re-open .psd file in Photoshop CS. To crop for the 30×40 print size without resampling this file: Select crop tool > enter in the crop tool parameters:
Width – 40 in height – 30 in, and resolution 90.
Drag the crop tool over the entire image and click view > snap to > document bounds, to keep the crop lines within the edges of the image. Click crop check mark to set crop.
You now have an image that is 40″w x 30″h at 90 ppi. Now is time you would want to apply any image enhancements to the photo enlargement, and the very last function would be to sharpen the image using the unsharp mask filter.
Send the photo enlargement to the printer through the RIP software and the image will be re-processed to 360 ppi, and print with amazing original image quality. We provide a chart of photo enlargement capabilities by digital photo megapixel resolution for an easy reference. All the photo enlargement sizes are figured utilizing the processing methodology described in this article.
Wide format photo enlargements yielding original image quality are absolutely possible if the original file is processed correctly and you avoid resampling the image pixels in your image editing software. Of course, high quality results require the use of these advanced software applications and this will also require reaching a bit deeper in your pockets.