RENDERNIG - 24in. X 24in. HEL P !

[Cesar R]

how can I render at 24in X 24in. I need to make a render for a clined and need to be able to be printed at 24in X 24in.

 

I plan to used brazil or maybe Max or LS, its an exterior scene, can someone give me advice?

[Tony]

The simpliest way is to mutliply the size of the image by the print resolution. Say 24" X 300 dpi =7200 X 7200 as the size of the image to be rendered.

 

You need to find out the printer resolution or pick a number that will give good results. 150 to 200 dpi is usually enough, depending on the printer. I would print at the lowest dpi you can and still get good results. It cuts down on render times and you probably won't see the difference in the printed image.

 

Hope this helps.

[Jeff Mottle]

This is somethng that gets asked a lot on almost every graphics forum and I have spoken to many print houses that don't underdtand pixels either becuase they always work with inches and dpi, so you are not alone. I have considered writting a brief PDF document with graphics to help explain the relationship that exists between all the print variables, but I'm board this afternoon so I'll do some of it here:

 

Basically when you are printing/rendering an image you have three variables to consider:

 

1. DPI/PPI (Dots per Inch/Pixels per Inch) Both are known as resolution.

 

2. Pixel size - measured in pixels (this is normally what you render to andiis how monitors are measured.

 

3. Print size - measured in inches (can be anythign but I'll use inches for convinience)

 

1. DPI/PPI

 

First you need to know what resolution your printer can handle. Some will say that they go to 1200 dpi or 600 dpi, but in practice you should never need to go bigger than 300 dpi, even if you are printing a 60 ft wide billboard. Just like digital camera's non-optical zoom abilities, printers use DPI to claim superiority in the industry.

 

DPI is the number of dots of ink that are put down by your printer onto a page over a one inch line. The amount of resolution that a printer can achive is based upon how close together the print head elements or jets are positioned. Of course it is a bit different with a 4 color press, but for now I'll just leave it at that. You may also notice that your inkjet will say that the vertical resolution will is different than the horizontal resolution. This is becuase in one axis the printer is relying on the proximity of the jets to each other, whereas the oher diection is related to the sensativaty of the rollers that are feeding the paper across the jets.

 

2. Pixel Size

 

I'm assuming that everyone is pretty familiar with pixel size as we deal with is on a daily basis. However, don't assume that your print house will be, because in many case they are not. You will usually need to give them an image size in inches based upon the resolution that their printer is capable. Don't try to explain it to them becuase they just won't get it.

 

Pixels are something that your monitor uses to describe the very small square dots (pixels) of light that are lit up by the guns of your CRT. (LCDs are different) Typically we say that a monitor is 72dpi.

A pixel translated to a page is usually represented by many dots of ink depending upon the print resolution.

 

3. Print Size

 

This one is pretty self explantory and is the image size on the page that your printer printed.

 

So you know what each one is but how do they relate to one another? As I mentioned earlier there are thee variables in this equation. To get one you must have the other two, so here are the possibilites:

 

For these examples let's assume that our printer is capable of 300dpi I am going to print an 8 x 10 image and my rendered pixel size is 3000 x 2400

 

You have Pixel Size and DPI and want image size:

 

This is useful when you want to know how big an image will print on your page if you do not allow the printer to scale the image at print time. (ie scale to fit).

 

===========================

 

Image Width = Pixel Width / DPI

 

Image Width = 3000 pixels / 300DPI

 

Image Width = 10 Inches

 

Image Height = Pixel Height / DPI

 

Image Height = 2400 pixel / 300 DPI

 

Image Height = 8 Inches

 

You have Pixel Size and Inches and want DPI

 

This one is not all that useful and I can't think of any reason to use it practially but here is it anyway.

========================================

 

Horizontal DPI = Pixel Size (Width) / Inches (Width)

 

Horz. DPI = 3000 pixels /10 inches

 

Horz. DPI = 300DPI

 

You can use the same equation for the Vertical DPI as well. Some printer are the same resolution in both axes.

 

You have Inches and DPI need pixels

 

This one is usful when you know that your printer can print 300dpi and you would like to print an image that is 8 x 10 and need to nkow how big to render your final image to do this. Of couse you could always render it bigger, but rendering time is precious so you never want to render more pixels that you have to.

 

=======================================

 

Pixel Width = DPI x inches (Width)

 

Pixel Width = 300 DPI x 10 inches

 

Pixel Width = 3000 pixel wide

 

Again the same formula can be used for pixel Height as well.

 

So now you know what each variable is and how they relate to one another. The biggest hurdle I suspect is how they relate to one anotehr visually, but that will have to wait for my DPF document.

 

Hopefully this helps some of you and does not confuse you even more. Even if you do not fully understand the why yet, you will at least have the formulas so you know how.

 

Cheers,

Jeff

[Cesar R]

Thanks, very informativa ans usuful

[bigcahunak]

Hi Cesar.

I hear this question quite often, and to be honest, if you have Photoshop installed on your computer its the easiest problem to solve.

Here is what you do:

• First, you know that you want a 24" x 24"
• Second, decide on printing res (depeds on printer of course, but usually between 150 to 300, right)
• Now, open Photoshop
• File > New (ctrl + N) and type in 24" for width, 24" for hight, and your desired resolution (say 200 pixl/inch). Mode doesn't matter, cause we are not really using this file for editing, only for pixel calc.
• Click OK to get your new blank image file.
• Now, go to Image > Image size and check your Pixel dimension. Should be 4800 x 4800 pixels in our case.
• Also, here if you decide that you want to change res, make sure "Resample Image" is checked (and bicubic is selected from the list) and now you can change the res and pixels will change for you.
• Thats it. Take those pixel dimensions and thats the size of your image you'll need to render.

Numbers are round figures in our case, but when you get into weird document size and funny resolutions, which you should try avoiding in the first plase, then this method is your perfect image size calculator.

Hope it helps.

Good luck.

[ingo]

math + artist= trouble

computer + math + artist= mo'trouble

 

Thanks for the explanation Jeff, but you can write a book about it, anyway you forgot LPI, otherwise nice beginning. I think we can make a new Forum just for this (Help i can render only 72dpi but i need more ).

 

Getting back to Cesars question, it depends on the printer used and of course how far your eye is away from the printing. With 60 cm x 60 cm i think you cant watch it lying on a desk, you put it on a wall, which means more distance eye to pict, which means less printresolution possible.

 

ingo

[seismograph]

300 dpi != 300 pixel/inch

 

I just want to remember you, that you talk about 1 inkdrop/color and that the way a printdriver place the drops depends on the paper.

 

If you have a 1200dpi printer i would say that in RL you may only have 1200/4 = 300dpi.

A HP driver normaly don't place the drops next to each other drop, but the printer will still not offer the full 1200pdi/2400dpi.

 

The question always should be:

 

Is it a image for the press -> make it huge!

you can expect full 600dpi or more in an offsetprint ..dont forget cmyk and embeded colorprofil

 

Is it only an image which will be used for an internal presentation -> 4000x4000px ~120-150dpi

 

In this size you can't use the image in a folder so you have a naturally distance to the image and then you can use lower resolutions.. it's similar to a normal poster you can see on the street with only ~50dpi.

[Cesar R]

thank you for help guys, I preciate it. In previous renders i've done I wasnt really sure to ensure the the imgage will not be pixelated when printed so large.

[Christopher Nichols]

Like Jeff said... the biggest mistake you can make is think... that you need 300 dpi because your printer prints are 300 dpi. Keep in mind, unless you are using a continuous tone printer, such as a dye-sub, or a Lightjet (http://www.cymbolic.com/products/lightjet5000.html) print, you are actually printing in half-tone. I make myself some rules generally that I try to follow. The rules are based on how big the image is. If the image is big, you will be looking at it from a few feet away, and will not need the extra res. Here is an outline of my rules...

 

8.5 x 11 inches

low 100dpi

mid 150dpi

high 300dpi

 

11 x 17 inches

low 100dpi

mid 150dpi

high 200dpi

 

18 x 24 up to 30 x 40 inches

low/mid 100dpi

high 150dpi

extra high 200dpi (complete overkill)

 

extra large prints 72 inches +

low / mid 70 dpi

high 100 dpi

 

For continuous tone images, I do what was recommened to me by the printer: between 150 and 200 dpi for any size print... maybe 300 for 8.5 by 11... but I would try 200 first.

 

BTW... the biggest aspect of print quality is NOT dpi, but printer calibration and GOOD paper. Paper makes the biggest difference. Never use cheap paper.

[Cesar R]

very nice table.. thank you for you help.

so at 150 I should be fine. I am tryin to keep in mind I will ge using GI to render the image.

[ingo]

Is it a image for the press -> make it huge!

you can expect full 600dpi or more in an offsetprint ..dont forget cmyk and embeded colorprofil

Sorry seismo, but thats totally dumb. Even the high glossy art magazines use only 175 LPI, which is roughly not more than 350 DPI.

 

ingo

[nisus]

Hey guys,

 

Try the adobe press books! I've read over six by now and they are really in depth The last I read was 'photoshop 5 studio techniques' (yes i still read the old books too...) and it gave a great explanation on all these ppi/dpi/lpi props

 

rgds

 

nisus

[seismograph]

yep, 600dpi are too much for images.

In Austria we have a zine called "wettbewerb" which uses real 300dpi for images and rasterised 600dpi for acad drawings. ....and this is not the best quality i saw in press.

[MegaPixel]

Just one quick question for you guys. I know in MAX 4, you couldn't render past a certain pixel size (Somewhere around the 6000 or 7000 range). Did MAX 5.0 address that issue or do you still have to do split renders and realign the images in Photoshop or whatever you choose to use? Naturally, this would only be an issue for people who want to do large renderings for printing purposes.

[Cesar R]

oh, I hope viz4 doesn have that problem...

 

 

ok, i just tryed to render a 24x36 in viz and its good , ill try larger than 7000 later