Image resolutions for submissions

[Chris_T]

Many calls for entry are now accepting digital images for jurying. But they either would not specify the resolution, or would ask for 300ppi. I know that the resolution for web/monitor is between 72ppi and 100ppi, and the resolution for desktop inkjet printing is around 300ppi. I am also aware that some submission images may be viewed on lcd projectors, and some may be used for newspaper or magazine PR. Here are the questions:

1. What resolution is needed for a lcd projector?

2. What resolution is needed for newspaper printing?

3. What resolution is needed for magazine or brochure printing?

I hate to send out 300ppi images without knowing if they are really needed.

[jani]

Many calls for entry are now accepting digital images for jurying. But they either would not specify the resolution, or would ask for 300ppi. I know that the resolution for web/monitor is between 72ppi and 100ppi, and the resolution for desktop inkjet printing is around 300ppi. I am also aware that some submission images may be viewed on lcd projectors, and some may be used for newspaper or magazine PR. Here are the questions:

Keep in mind that while the final display may be targeted towards a specific medium, such as those you mention here and below, the jury may judge the image's quality based on the image at  full detail.

It really depends on the purpose. E.g.: will the winner only be presented in a specific way, or may it result in sales of prints of greater quality than those displayed?

1. What resolution is needed for a lcd projector?

If it's a fairly normal projector, it might do 1280x768, 1280x960 or 1280x1024. Some more expensive models are closer to 1080p. Some really expensive models give you "4k" resolution, or essentially around 8 megapixels total image size.

If you provide an image that's big enough for 1080p (essentially 1920x1080 or greater), that will most likely be enough.

2. What resolution is needed for newspaper printing?

100-150 PPI, depending on the quality of the paper.

3. What resolution is needed for magazine or brochure printing?

That varies a lot for magazines, from around 133 LPI to 200 LPI (requires 200 PPI to 300 PPI), and for the kind of brochures. High quality magazines and brochures would probably require 300 PPI. I'm not certain that there is anyone asking for more, but perhaps someone else can correct my numbers.

[Chris_T]

Jani, thanks for the response, again.

Keep in mind that while the final display may be targeted towards a specific medium, such as those you mention here and below, the jury may judge the image's quality based on the image at  full detail.

It really depends on the purpose. E.g.: will the winner only be presented in a specific way, or may it result in sales of prints of greater quality than those displayed?

Agreed, and that's why I asked for the resolutions for different media. With your answers, I now know what to submit, whether a call spells out the specific medium or not.

If it's a fairly normal projector, it might do 1280x768, 1280x960 or 1280x1024. Some more expensive models are closer to 1080p. Some really expensive models give you "4k" resolution, or essentially around 8 megapixels total image size.

If you provide an image that's big enough for 1080p (essentially 1920x1080 or greater), that will most likely be enough.

If I understand correctly, that menas in PS Image Size, 1080x780 at 72ppi? It would be identical to what I would send for a regular monitor.

100-150 PPI, depending on the quality of the paper.
That varies a lot for magazines, from around 133 LPI to 200 LPI (requires 200 PPI to 300 PPI), and for the kind of brochures. High quality magazines and brochures would probably require 300 PPI. I'm not certain that there is anyone asking for more, but perhaps someone else can correct my numbers.
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So PPI rougly equals 1.5xLPI?

[DiaAzul]

Many calls for entry are now accepting digital images for jurying. But they either would not specify the resolution, or would ask for 300ppi. I know that the resolution for web/monitor is between 72ppi and 100ppi, and the resolution for desktop inkjet printing is around 300ppi. I am also aware that some submission images may be viewed on lcd projectors, and some may be used for newspaper or magazine PR. Here are the questions:

1. What resolution is needed for a lcd projector?

2. What resolution is needed for newspaper printing?

3. What resolution is needed for magazine or brochure printing?

I hate to send out 300ppi images without knowing if they are really needed.
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Bear in mind - the judge will only have 5-10 seconds to judge your picture first time round. Perhaps a bit longer after the shortlist has been made - initial impact is all important. If it is done on a projector the 1280x1280 is sufficent - if submitting JPEG the most important is to avoid artifacting (shows up in the sky particularly).

If they want to print the images of winners photographs then they will ask you for higher resolution images if required.

[jani]

Jani, thanks for the response, again.

You're welcome!

(Regarding 1080p)

If I understand correctly, that menas in PS Image Size, 1080x780 at 72ppi? It would be identical to what I would send for a regular monitor.

No. Just like I wrote, 1080p = 1920x1080.

PPI is irrelevant, since you won't know the projection size. If a projection is e.g. 4 meters wide, and the projector is capable of 1280x768, that is about 8 PPI, unless I fumbled my calculations.

If I could assume a regular projection, I'd probably submit a 1920x1080, and set the PPI for something that's close to current monitors (100 PPI). Opinions vary here, I guess.

So PPI rougly equals 1.5xLPI?

According to what I've learned, yes.

David's response is also quite relevant, of course.

[Chris_T]

Bear in mind - the judge will only have 5-10 seconds to judge your picture first time round. Perhaps a bit longer after the shortlist has been made - initial impact is all important. If it is done on a projector the 1280x1280 is sufficent - if submitting JPEG the most important is to avoid artifacting (shows up in the sky particularly).

If they want to print the images of winners photographs then they will ask you for higher resolution images if required.
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Understood. For that 5-10 seconds, an image must have impact to catch the jurors' eyes and also must not have any "obvious" technical problems. Life would have been a lot simpler if the jurors can specify clearly the pixel dimensions *and* PPI that will suite their viewing conditions during jurying. Then they can follow up with high resolution files for printing, if necessary.

But unfortunately, many calls would not specify anything or would ask for 300PPI. When I question them about it, I have found two reasons. Some have no clue about resolution or PPI, and some want to make life easy for themselves by asking for 300PPI, "just in case they need to print them".

My intent is to minimize the need to send 300PPI images to prevent them from falling into the wrong hands.

[Chris_T]

You're welcome!

(Regarding 1080p)

No. Just like I wrote, 1080p = 1920x1080.

PPI is irrelevant, since you won't know the projection size. If a projection is e.g. 4 meters wide, and the projector is capable of 1280x768, that is about 8 PPI, unless I fumbled my calculations.

If I could assume a regular projection, I'd probably submit a 1920x1080, and set the PPI for something that's close to current monitors (100 PPI). Opinions vary here, I guess.
According to what I've learned, yes.

David's response is also quite relevant, of course.
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I'm unfamiliar with LCD projectors and projection sizes. From your posts, PPI seems to mean something different for LCD projectors and for regular monitors.

Regardless of a monitor's size, a file with 100PPI would be sufficient and anything higher would not make any difference.

But for LCD projectors, a file's PPI is "scaled" to the projection size. In your example, does a "regular projection" size mean 1920x1080? Is that also the best viewing size (which I assume the jurors would use)? For this size, will PPI above 100 make any difference? When the projection size is larger than regular, what is the scaling formula? I assume that is PPI is "scaled" down significantly, it would mean a loss of quality.

[jani]

But for LCD projectors, a file's PPI is "scaled" to the projection size. In your example, does a "regular projection" size mean 1920x1080? Is that also the best viewing size (which I assume the jurors would use)? For this size, will PPI above 100 make any difference? When the projection size is larger than regular, what is the scaling formula? I assume that is PPI is "scaled" down significantly, it would mean a loss of quality.

You're making this a lot more difficult than you need to.

An LCD or DLP projector doesn't really have PPI, except on the chip, and that's hardly useful.

If I project to a screen that's 1m wide, I get one density, and to a 5m screen, another one.

The only thing that remains constant, is the amount of image pixels the projector is capable of displaying.

If you deliver a file with minimum dimensions of 1920x1080, you'll probably be on the safe side for this kind of viewing. Most projectors do either 1280x768, 1024x768 or similar.

Semiprofessional or professional projectors, for instance for digital theatres, may deliver 1920x1080 natively ("2K resolution"), some even approximately 4000x2000 ("4K resolution"). The risk of anyone in a jury actually having access to a 4K projector is fairly low, the price is prohibitive even for theatres, but it's coming down.