I was just wondering what the recommended resolution (dpi)is for print renderings is. I think that rendering at 300 dpi is a bit excessive so is there a resolution that is some how falls somewhere in between quality and rendertime? Also does anyone understand what exactly the image size dialog box does in the output tab of the render room? Sounds like a silly question until you start messing around with the dpi settings and it seems to scale the input image size (in pixels) dependant on the dpi entered. It would make sense if I could input the image size in inches but if I enter a 1000x1000pixel image at 300dpi then it renders at a different size. Only 72 dpi gives me what I am expecting. Thanks

72 dpi generates a 1 to 1 correspondence with what you put in for the original pixel resolution. 300 dpi is not an unusual resolution for printers and rendering at that dpi will produce excellent results when put to paper. You should also consider posting this in the printing forum! They have lots of people who know tons of stuff over there about this very thing! -Kix

Thanks. I did not see the print forum.

For offset litho/printng press type of work 300dpi at actual size is essential. For large format inkjets used in trade show backwalls or posters, typically 150dpi at actual size is satisfactory. For hi resolution desktop printers (ex. Epson Photo 2200) 200dpi at actual size. If you are working with other sizing software like Genuine Fractals or us Photoshop to up-size the image after rendering you can get away with half of the dpi's I mention above. However, there will be a little fuzziness and loss of clairity in the process. Also, Photoshop works best when the increase in size follows even increases like 200% or 400%. Increasing size to 400% would really be pushing your luck though. Size increases like 160% creates noticible pixilation. For Hi dpi renderings, make sure that you don't have Carrara doing any unnescessary calculations. Turn light rays down do 4 unless you have transperency that has more than for sides to penetrate and eliminate options like Refraction if you don't need it. Mark

Mark and Kixum are correct above, but I'd add one thing to Kix's comment. 72 DPI gives you a 1 to 1 correspondence when you're viewing your image on a PC monitor. (Macs use a different DPI -- something around 90? I don't remember for sure.) At any rate there are some basics about Dots Per Inch that may help understanding here. I do a fair amount of rendering of stuff that winds up in print, so I've had to do some serious head scratching on this.... Let's say you have an image that's 4 inches by 6 inches. If you're viewing it on your monitor and it's 4 x 6 inches, it's 72 dots per inch (DPI), so it's going to be a resolution of 288 x 432 pixels. (We're assuming square pixels here; DV pixels are a different shape and so they're different in the horizontal and vertical ratio. Let's not go there for now.) Now, if you're looking at a 4 x 6 inch image that's been printed by a professional, offset post-card printing house, it's likely an image that was 300 DPI, or your render would have to be 1200 x 1800 pixels. Viewing a 4 x 6 inch 300 DPI image on your computer would make it stretch out to 16.666 inches by 25 inches, because the computer can only display 72 dots per inch. It's confusing, but if you just calculate the size you want the image to be for printing and multiply the number of inches by the DPI requested by the professional print house, you'll come up with the resolution you need to render at, regardless of the DPI setting you render at. Hope that clarified things more than made mud of them.... - Dex

Some of this discussion relates to what the eye can see. An image will not appear sharp unless there is detail to the limit of your vision. For the average young person with excellent eyesight the "mark eight eyeball" can resolve features about .1mm apart. This works out to about 250 dpi. It is my understanding that magazine art is around 150-200dpi and fine art printing about 300 to 350 dpi. What confuses me is that it takes 4 spots of ink (CYMK) to create a dot doesn't it? So how does this work in when figuring print resolution?

Attached Link: http://www.scantips.com/no72dpi.html

Hi guys, just thought I'd sneek over here from the forums I usually peruse. I don't use Carrara, but have seen some interesting threads in here lately. Your computer monitor doesn't actually display in dpi. It displays in x by y pixels. The dpi is only important for printing. This is such a big area of confusion for people doing cg and it never seems to get any better. There is a thread along these lines in the Bryce forum at the moment, about sharpness and dpi etc. See the attached link for a more in depth discussion about dpi and monitors.

Thanks guys for the help! I am even more confused :) but I think I ma more likely to figure this whole thing out. Gonna have to put more time into understanding this than I thought. It is more complicated then it looks. One thing that is great about using Carrara for print is the small render times. The fact that I am rendering at 4000px or more is not much of an issue since the renders are so fast. Thanks again.

Thanks RubiconDigital for the link to the scan tips. Excellent information clearly stated. This one gets a bookmark for sure. A lot of the problems come from a misunderstanding of the words involved "resolution" being a prime offender IMHO!

You're damn right there sailor ed. I think the term "high resolution' in particular is THE most over used one in computer graphics.

This whole process is really simple as pie. I understand there is a lot of confusion but there is a way to make Carrara render great images everytime for print at the size you seek/need. This is the only thing I use Carrara for---CMYK print images. A. Go into Photoshop. Find out what the image size you are after is in pixels at 300 dpi. B. Then go inside Carrara/render/output and enter the pixels you got from Photoshop. Keep the resolution inside Carrara at 72 dpi and then select keep proportions. Pixel aspect ratio remains at 1. C. Then render. The output image will be a very large 72 dpi image. D. Open it in Photoshop (it will be a large 72 dpi image -- not 300 dpi [yet]) and set the inches to what you are after and E. then set it to 300 dpi. For press work don't use images below 300 dpi. It is better to stick with the STANDARD when going to press. I promise peoples eyes will pick-up the difference if you use lower resolution images for the press. Hey, but go ahead and experiment if you are into unexpected and less than perfect results. This method produces wonderful sharp images ready for print after you convert to CMYK of course. It works without fail everytime. No need for any extra confusion or effort. I feel the goal is the END RESULT (predictable and good). There is a lot to get confused about if you let it. Go to the thread: "Hard drive meltdown?" as this was dicussed in length Good Luck, steama

We can all thank Georges Seurat for his pioneering work in pointillism to advance the theory of, and reproduction of, color. The confusion is in the terminology and different printing technologies used to reproduce the image. Many people incorrectly interchange dpi for Lpi. PPI is for pixels per inch that your monitors resolution is manufactured at. I believe most to be around 92 ppi for crts. DPI (or dots per inch) is for the original image resolution. The actual printed size and method of reproduction should determine the number of dots per inch to render at. SPI (spots per inch) is the terminology for how laser printers & most photo printers output resolutions are measured. Photo printers are typically 1200 + spots per inch horizontally. You can imagine a grid that is 1" wide with 1200 potential spots or color. When the various colors are called for to "print" the nozzles either print that color dot or they don't. It operates much like the old dot matrix printers did, if you remember them, only at a much finer resolution. LPI (lines per inch or screen frequency) is the measure for offset printing screens used to burn the image printing plates, one for each color (CMYK). The LPI will vary depending on the type of paper being used but in general a line screen of 150 or 175 is common for coated offset paper. The general rule of thumb is to use an image resolution of 2 1/2 time the lines per inch. Hence, a one inch final printed image size printed at 150 lines per inch should be 150 LPI x 2 1/2 = 300 dpi. The reason that the image for CMYK offset printing needs to be higher then the one for the ink jet printer is a matter of ink spot size relative to the "spot" at which it is to print. Not only does each color have the potential to be "on or off" for the spot at which it is to print (like for the ink jet printer) but also the "size" of each ink spot is variable between 0 & 100% for that particular spot on the matrix. Short story is to use the 300 ppi (to the actual printed size) as others have said.

Attached Link: http://www.midazo.com/dominos/archive/slammin.html

i used carrara for the renders at the attached link. obviously they were printed. largest dimension was 17 inches, and yes, 300dpi is the industry standard for offset and commercial web printing. i use a really mechanical, basic way to figure out what size i need to render to. if the above posts dont answer your questions, just e-mail me and i can tell you what i do. :m

Thanks for all of the replies. Nice Flyers midazolam.