image size required for printing formula?

[Lee Ballard]

I usually tell the customer as high a resolution as possible.

(sorry probably not the answer you were looking for)

[Fred McLean]

Ditto 😛

[David Rowland]

yep, but if they start resampling it to make it bigger then problems start

[Peter Dee]

1/4 actual size output file at 300dpi is a minimum I think.
Any photos must not have been scaled up to get the dpi, only scaled down from the original.
Must be CMYK.

[Peter Normington]

quote Peter Dee:

1/4 actual size output file at 300dpi is a minimum I think.
Any photos must not have been scaled up to get the dpi, only scaled down from the original.
Must be CMYK.

I really cant see why this formula is supposed to be the be all and end all?
if you were printing a banner 20mx20m at this resolution you would have to wait a week to rip it would you not?
and Why CMYK?

Explanations would be welcome, I know its requires a compex answer, but the dpi or resolution on original image, does not always relate to the output.
indeed far from it.

Many factors need to be considered, or so I am told 😀

Peter

[Ali Osman]

quote Peter Dee:

1/4 actual size output file at 300dpi is a minimum I think.
Any photos must not have been scaled up to get the dpi, only scaled down from the original.
Must be CMYK.

That info is way out !
‘Must be CYMK’ ? *rofl*

Think about that comment

[Peter Normington]

quote Ali Osman:

quote Peter Dee:

1/4 actual size output file at 300dpi is a minimum I think.
Any photos must not have been scaled up to get the dpi, only scaled down from the original.
Must be CMYK.

That info is way out !
CYMK?, me thinks not

Hi Ali

Can you elaborate?

Peter

[David Rogers]

The best advice so far has been…the best they can give you. there are no rules…nobody will give you origianl photos 20metres long at 75dpi…so working on a formula won’t work.

I’ve taken truly crappy pictures given to me by clients and made large prints by resampling them, so that is not a no-no either…it’s just down to how good you are at tweaking the image…and how far it’ll be viewed from. No point in a 1400dpi print to be viewed from 20 feet away.

CMYK or RGB makes sod-all difference in the image supply side…and hardly any until it’s put to your RIP software (some small changes may be noticable under certain conditions)…as RIP will convert it to CMYK anyway.

Hey, just my opinion…

ps. as an example, a client of mine will be getting a bit of artwork on the side of his sprinter so took several 6MP images. These were never designed to be printed over 8" wide…I’ll be pushing it to 48 inches wide at around 150dpi interpolated, on a very high quality setting print…take what you can get and work with it.
Dave

[Fred McLean]

Did a site board for a housing assoc. a year or so back.
The artwork supplied was cr@p and told them so,just print it they said!
On the bench you could virtually see the individual pixels but standing only 10 ft back it looked spot on 😀 😀

Board size was 8ft x 6ft

[Peter Dee]

quote Ali Osman:

quote Peter Dee:

1/4 actual size output file at 300dpi is a minimum I think.
Any photos must not have been scaled up to get the dpi, only scaled down from the original.
Must be CMYK.

That info is way out !
‘Must be CYMK’ ? *rofl*

Think about that comment

Hey I’m no expert, only going on what I’ve been asked to supply to printers.

So better than me having to ponder how it’s done, why don’t you get up off the floor and enlighten us?

[Tobias Redig]

I’ve seen some odd results when mixing RGB and CMYK in the same file. Both systems has a different gamut range, so if you’re unlucky you might get some iffy results. Black for one is totally different in CMYK and RGB, RGB black will print using alot more ink then CMYK black and might smudge more then using CMYK black.

I prefer to always convert everything to CMYK before printing.

[Stephen Morriss]

I have never got the 1/4 size at 300 dpi thing, the file contains the same amount of information anyway.
Also if my maths is right 300 dpi at 1/4 size is 72dpi at print size.

As a general rule don’t bother going over 160dpi at finished print size, you’ll not see any improvment.
There is a guide in the Roland mystery book (search on there web site) it gives recomended dpi for viewing distance and they also recommend using RGB as the file sizes will be smaller (3 bits per colour instead of 4 with CMYK)

But as David has said it usually ends up being the best your customer can give you.

Steve

[Rod Young]

quote David Rogers:

I’ve taken truly crappy pictures given to me by clients and made large prints by resampling them, so that is not a no-no either…it’s just down to how good you are at tweaking the image…and how far it’ll be viewed from. No point in a 1400dpi print to be viewed from 20 feet away.

If one is having trouble with a large resampling, then another thing to consider is resampling in stages. This was a common trick in older versions of PhotoShop, such that latest versions now resample in stages automatically.

Rod

[graffica]

If you receive crap artwork, you´ll get a crap end-product.
You can only be as good as what you´re given.

I do a lot of roll-up banners 200 x 85cms. x 75dpi….always RGB, (assuming I receive good images in the first place) which I e-mail FULL SIZE in Photoshop or Corel12 to a digital print company.
These are mainly for exhibitions and retail display, therefore viewed close So far, all my customers are happy with the output.

Chris A.

[Chris Wool]

quote :

If one is having trouble with a large resampling, then another thing to consider is resampling in stages. This was a common trick in older versions of PhotoShop, such that latest versions now resample in stages automatically.

Rod

still do it the oldway any idea when it changed please rod

chris

[Rod Young]

quote Chris Wool:

still do it the oldway any idea when it changed please rod

I believe it was with the CS2 product, which equates to PhotoShop 9.

Rod