Do I Make Graphic Design for Print Size Correctly?

[TechnicGeek]

Hello,

I have been designing for not long time and I still feel that I don't connect some dots properly.

I am mainly interested in knowing how to make final design file print compatible.
I want to make sure it will 300 DPI and be in high resolution to be printable.

Here's my workflow:

1. I download free clipart/vector and immediately open it in GIMP
2. I do adjustments, add other elements from other files, add text
3. Before finishing and exporting graphic I set print size to 300 DPI in "Image" > "Print Size"
4. I flatten everything and export into .PNG ready to print

- Do you see any mistake in this process that would make final design not print-ready?
I am concerned about opening .JPG/.PNG graphic elements. Must they be 300 DPI before I even start working with them?

- Does it matter when I set "Print Size" to 300 DPI? Must it be done in the beginning or as long as it's done before
exporting project to final design, it does not matter?

- I often would create new page where I would modify graphic elements and I would not set DPI before I do that.
Is it bad?

Thanks!

[Blighty]

Two important bits of information missing.
1. What is your print size (in inches, cm, ...)?
2. What is your image size in pixels?

If you want to print 1"x1" at 300 dpi you need an image size of 300x300 pixels.
If you want to print 10"x10" at 300 dpi you need an image size of 3000x3000 pixels.

Another thing:
Don't flatten. SAVE as xcf. EXPORT as png.
If you want to make edits then open your xcf and do them there.

[rich2005]

All sorts of ways, as long as you understand that Gimp works in pixels. It is important to start of with an objective in mind.

A few screenshots so not in-line look as required.

You know that you are going to print your design (on a t-shirt?) so you must have some idea of the size required. For this example I use 15 cm x 15 cm.

Create a new canvas like this: https://i.imgur.com/rDyBWsI.jpg
1. File -> New
2. Use the advanced options and set resolution first - I use 300 ppi
3. You can use real-world units, cm here, and enter the required Width and Height 15 x 15 cm
4. Note: there will be some rounding to match the size in pixels shown as 1772 x 1772 pix.

For importing vector and clip-art https://i.imgur.com/3IoJZ5c.jpg
5. File -> Open as Layers
6. Set the required resolution (300 here)
7. Set width or height to suit the canvas size. Canvas size is 1772 pix so I use 1700. You could use cm there as an alternative.

For importing raster images. https://i.imgur.com/y9otxmu.jpg
8. File -> Open as Layers
9. There is no choice on size, it is whatever the image is in pixels. It is possible to scale the layer up or down once imported but beware of degradation.

The working image https://i.imgur.com/nlNbeRH.jpg
You can check the properties or the print size, but you started with 300 ppi and that is what is used (unless you change it)

Note: anything copied and pasted into the image will automatically use the image 300 ppi.

The reverse is not true. Copy that image and paste into a 96 ppi (usual default ppi) image and the resulting image is 96 ppi

Remember to Save the image as a Gimp .xcf which saves layers, masks, paths etc.
To send to a printer, Export a png, that saves any transparency

[TechnicGeek]

(12-09-2017, 05:59 PM)rich2005 Wrote: Create a new canvas like this: https://i.imgur.com/rDyBWsI.jpg
1. File -> New
2. Use the advanced options and set resolution first - I use 300 ppi
3. You can use real-world units, cm here, and enter the required Width and Height 15 x 15 cm
4. Note: there will be some rounding to match the size in pixels shown as 1772 x 1772 pix.

And I was setting DPI later in the process, often after importing/opening graphic elements I would use in a design... Sounds like these layers were imported as 72 DPI (default setting for new image)? Were they later converted to 300 DPI after I set up DPI later?

I do not open images the way you describe. I just start GIMP and drag & drop image, mostly already in high resolution. Does that change anything?

Does it matter whether I set new image as 15" or 15cm when it comes to calculating resolution? Will 10x10 x 300 DPI be same with " and cm?

(12-09-2017, 05:59 PM)rich2005 Wrote: 9. There is no choice on size, it is whatever the image is in pixels. It is possible to scale the layer up or down once imported but beware of degradation.

You mean even scaling down from high DPI causes degradation? I only heard the other way around does...

[rich2005]

(12-10-2017, 09:35 AM)TechnicGeek Wrote: You mean even scaling down from high DPI causes degradation? I only heard the other way around does..

Yes, you are throwing away pixels. Up to you to decide if the result is acceptable.

There are measures used to improve scaling down. Pre-blur the original by a suitable mount. For 50% use Filters -> Blur -> Gaussian blur with a value 2 for 25% try 4

I have never scaled anything less than 25% and had a really good outcome.

However, printing on fabric is not the same as on photopaper and you will get away with less-than-wonderful.

[Blighty]

(12-10-2017, 09:35 AM)TechnicGeek Wrote: Does it matter whether I set new image as 15" or 15cm when it comes to calculating resolution? Will 10x10 x 300 DPI be same with " and cm?

You mean even scaling down from high DPI causes degradation?

You need to remember: Gimp works in pixels, not dpi.

A 15"x15" image @ 300 dpi will give a size of 4500x4500 pixels
A 15cm x 15cm image @ 300 dpi will a size of 1772x1772 pixels.
You need to get the size in pixels correct right at the start.

Scaling does not change the dpi. It changes the size in pixels. Scaling will throw away (or create) pixels as required. This causes degradation.