[Failure due to ignorance!?] What are the resolution settings you should know before sending print data?
My name is Matsumura , and I am the CEO of PHOTOPRI, a large-format printing service offering exhibition-quality printing.
I also work as a professional photographer!
This time we will introduce you to the "resolution" that is important for producing beautiful printed materials!
table of contents
1. First of all, what is resolution?
When placing an order with a printing company, you may have seen the notation "The recommended resolution is XX ppi."
Even with PHOTOPRI, the recommended resolution is basically 300 to 350 ppi.
The number with the unit "ppi" or "dpi" is the resolution!
(The difference between ppi and dpi would take too long to explain, so I will skip that.)
If you submit an image with a low number (poor image quality), the printer's capabilities will not be fully utilized and the finished product will be rough.
Digital images are made up of tiny particles of color.
These particles of color are called "pixels" or "picture elements."
The more pixels there are, the more detail you can create, resulting in a better image quality!
(The term "megapixels" is often used to describe the resolution of images captured by cameras.)
The unit of resolution "ppi" is an abbreviation for "Pixels Per Inch."
This means "how many pixels are in one inch square."
The unit of inch is not very familiar to Japanese people, but
Since 1 inch = 2.54 cm, it may be easier to remember this as "how many pixels are in an area of 2.54 cm."
Roughly speaking, resolution is the density at which pixels are arranged .
2. Common mistakes when changing resolution
At PHOTOPRI, if an image has extremely low image quality, we will contact you to confirm before printing it.
(Please note that the level of roughness that is acceptable is subjective and cannot be determined with any certainty.)
A common mistake when responding to a complaint that the image quality is poor is to simply change the resolution numbers of the same image .
For example, in Adobe Photoshop you can change the resolution from a screen like this.
When trying to edit an A4 size (297*210mm) image with a resolution of "72" to "350"...
The actual size of the image has been reduced to 61*43mm!
Resolution refers to the density at which pixels are arranged , so the higher the resolution, the smaller the actual size of the image will be .
Even if the resolution numbers are correct, this is not suitable for printing on A4 size paper.
In other words, no matter how much you change the resolution, the image quality will not improve unless the original number of pixels increases .
In Photoshop, if you check "Resample", you can change the resolution without changing the image size,
This is a function that allows the application to forcibly fill in the missing pixels.
Please note that using "Resample" does not improve image quality!
The original number of pixels is
If it's digital illustration, create a new canvas before you start painting .
If it's a camera, when you take a picture/when you export the image
It has been decided.
It is possible to force high image quality using AI, etc., but that is a different technology so I will not go into detail here.
I wish PHOTOPRI's service could improve the quality of my customers' images...
3. Summary
When preparing images for printing
" ① At the actual size you want to print"
" ②Adjust to recommended resolution"
Ideally, these two criteria would be met.
I want to create an image in A4 size (297*210mm) with 350ppi, but how many pixels do I need? If you are unsure, there is an automatic calculation tool like this one that can help you!
(Link to an external site)
If you are unsure whether your images will print clearly, please contact us in advance!
