Hello, I have a (maybe silly) question.
I am preparing a vinyl cover case. I asked for details and the only answer the printer gave me was " 3000 X 3450 dpi".
That means what? If the dpi is 300 (typical for high quality print) then the dimensions are 11,5 X10 in.
But some printers print at 304 dpi. That means that the dimesions are a bit smaller.
I asked for a technical drawing (template) to fit my design, to be sure about everything but there was no reply.
What made me question everything is that the printer told me that the design should be “square”.
The printer is being vauge. They are probably confusing DPI (print resolution) for pixels, so your document might need to be 3000 x 3450 pixels.
You’re right that it’s rectangular and not square. There might be a reason for this.
Ask them if it’s a perfect square as the dimensions don’t equal a square - unless some of it is for bleed, where the vinyl cover wraps and glues.
So that makes it even more important you get a template so you can see the glue flaps/folds/etc.
Keep at them for a template, tech drawing, or a previous supplied artwork made blank that you can use.
If you don’t get anywhere then do it at a square size 3450 × 3450 px at 300 dpi and leave extra bleed that can be cropped if needed, so no text/logos etc outside the 3000 square area, only expendable artwork.
The “300 dpi myth” mainly applies to lithographic printing, where the LPI (lines per inch) is typically 150 on the output device. The actual optimal resolution is:
1.414 x 150 = 212.1 dpi
(In a 1x1 grid rotated 45 degrees, the diagonal length (distance from one dot to the next along the halftone screen) is 1.414)
Newspapers for example use coarser paper the LPI is lower, typically 80–120. Using the same formula
For 80
1.414 x 80 = 113.2 dpi
For 120
1.414 x 120 =169.68
Over time, this got rounded up to 2 x 150 = 300 dpi, which became the standard.
(Nyquist sampling rate suggests that PPI should be at least 2x the LPI)
I’ve never heard of anyone printing at 304 dpi, probably a typo.
The key takeaway 300 dpi isn’t a universal rule, it depends on the printing method and output device.
Thanks for the immediate answer!
Actually here in Greece many printers ask for 304 dpi (even the tutor at the graphic design school told us why 304dpi is better than 300, but I don’t remember why).
I will insist on a template, because I really want to know how to place my artwork, and the overall layout.
Can’t think of a single reason why 300 is relevant never mind 304.
Love to know more - if you find out let us know - very interesting, could be a conversion thing from different units.
No idea why it would be better??? More resolution doesn’t mean much in litho print, it can actually be worse.
Maybe it’s a digital printing standard adopted in Greece.
Anyway - you still need a template or take a guess at the larger size.
Or just do what they want and keep everything in the 3000 square
And send them the final design at the dimensions they requested.
Did the printer really say DPI or did he say PPI? They mean completely different things. The only thing I know of that prints at 304 ppi are some thermal printers.
In today’s terminology, DPI refers to the number of tiny dots of ink or toner per inch printed in digital printing.
PPI refers to the number of pixels per inch in digital images.
LPI refers to the number of halftone dots in offset or letterpress printing.
Sometimes, people say DPI when they mean PPI. When people say 300 DPI, most printers and designers let the terminology mistake pass and assume they meant PPI. However, sometimes the mistake matters and confuses things. For all I know, the printer is digitally printing your vinyl case at 304 dots of ink per inch and needs the file composed of 3000 x 3450 pixels. However, 3000 x 3450 is a problem that needs to be cleared up if the image needs to be square.
There’s miscommunication taking place, and only the printer can clear it up unless they’re also confused. If they’re not responding to your inquiries, give them a call and insist on an answer. Sometimes printers aren’t good at communicating.
By the way, @Smurf2’s explanation regarding PPI is correct. Knowing this stuff is important, and it should be mandatory that it be taught in schools.
300 ppi is simply a rule of thumb for 150 lpi offset printing. It’s a higher resolution than needed for 150 lpi printing, but it’s easy to remember and provides a bit of wiggle room in case the image needs to be enlarged a little in the layout applicaiton.
The printer was again very vague and he explained " 3000 X 3450 dpi for digital"
That was the answer. Then again I had to ask him… that he meant… digital promo for spotify etc! Because he will do that aswell. So he did mean pixels and nothing more. About printing we will talk later he said.
That’s all!
Thanks for you answers btw!
Yeh that’s not a size.
There’s no such thing as “3000 X 3450 dpi.” It makes no sense.
Were you talking to a sales person, the front desk receptionist, a help desk person, or someone else who might not have known what they were talking about? If so, is there a way to bypass these people and ask to speak to a prepress person? Dots per inch aren’t measured in X, Y coordinates. It’s a bit like measuring a kilogram of water in centimeters — nonsensical.
I know! Probably he is the salesman or some assistant.
I have to deal with such things sometimes 
Hopefully they will send me a template.
We all do, so you have my sympathy. 
Yep, was asked for a hi-res jpeg of a logo for a video presentation so kept it 3840 (w) × [proportional height] px at 72ppi.
I sent it to on to them and they wrote back that they changed it to 300 DPI and sent it on…
Not that it makes a difference… but still annoying.