Hey all, I'm scanning some hand draw images into photoshop at around 300dpi that were created on 8.5x11" paper. I'm planning on rendering these images, and then I need them to fill up an 11x17" page. If I scan the images in and then enlarge the image at 300dpi, it seems to really slow down PS when I'm trying to render it. The airbrush ,for example is really slow, as sometimes I have to use a size 900 brush. My question is, can I keep the image smaller while rendering, and then blow up at the end, or can I use a lower dpi? How will the image quality be? Thanks

It should depend on the style of art you do. If you have a comics style, you can scan the line art at high res and color a low res copy of it; at the end, you can up res the color and multiply/merge it with the original black and white line art scan. The edges will look sharp, and the color -- if it's smooth and not textured -- will look fine. If your style is more textured, then increasing the resolution near the end won't work as well. You'd have to lay down your base colors in the low res phase, then up res before you get into doing the detail.

Well, what i'm doing is renderings of cars - so . . . Which method do you think would work best? If I always keep the resolution the same, does it matter how big the image is while I'm working on it? Can I shrink the image, and then enlarge it at the end?

You can, but the edges will lose their sharpness if you're straight digitally painting the art at low res. If, however, you use paths -- and I mean paths that are attached to the layers -- you can maintain the sharp edges so long as you keep the colors or color transitions smooth and somewhat extended beyond the path. Using paths would probably be the best method for rendering cars.

Message edited on: 06/12/2004 18:29

I'm sure you know the a 300 dpi 11x17 has more pixels and take up more ram/ diskspace than one @ 144 dpi. both are 11x17. more often than not it's not recomended to enlarge. shrink and enlarge back, the main reason is that photoshop will "interpelate" - guess image iformation, I'm impressed with the different bi-cubic re-sampling options available is CS, but, in the end it's inventing detail that is not there. if you paint / render a 11x17 image, on any thing smaler than a 11x17 canvas and enlarge, prepare for less detail. if your low on memory see if exit-ing all other programs, helps I think there are options in PS concerning memory, I think you can also adjust how much, PS is dedicating it's self in the preferences.

That aside, it (rendering at lo-res and then enlarging) CAN be done without much loss of quality if there is not a whole lot of detail involved. A lot of pros use that technique to save themselves time, but only in the ways that I described above. For instance, a lizard character that I did for one of my clients was originally done at 500 x 900 -- image attached -- but I did the character in layers, and each layer had a path (it's like each layer having a mask, but the masks are in vector form). The actual art on each layer was just a flood fill of color with some airbrushed shadows and highlights, but all the color transitions are smooth. The text is not rasterized, and I use styles to give it a 3D look. Notice that the only thing with any real texture is the background. When I enlarge the image, it will lose its sharpness, but because it's just a background and not meant to detract from the character, having it blur a little during the process doesn't concern me. In the next post, I'll show you a cropped detail of the image when I blew it up to 1500 x 2500.

Here's a cropped detail from the 1500 x 2500 version, which I did AFTER I did the original piece when the client asked for a larger version to put on a poster or a Cafepress t-shirt. Because the text was not rasterized, it kept its smoothness, and because each part of the lizard was a path on a layer, the edges remained sharp. If you look really closely, yeah, you can see slight pixelation in the green of his skin. If I wanted to, I could put a little gaussian blur on it to smooth it out, but the edges will remain sharp because they're made by paths. Even the black outline will remain sharp because it's rendered with a style stroke (that I had to tweak to make it wider after the enlarging, of course; the pixel size stays the same otherwise). As I mentioned above, there's some blurring of the background texture, but since that's not the focus of my image, I didn't care. So there you go -- one example of successfully enlarging an image in Photoshop without much loss of quality. If I could remember the colorist's name, I'd point to an artist who uses the comics art style enlarging technique I mentioned in my first post.

What do u guys actually mean with rendering? Is it when u use a filter on it? And Aprilgem, wasn't the lizard made in a vectorial program such as illustrator? Then those vector images u can scale without having to concern about bad resolutions... Just to understand fully what u mean ;-)

Ok, thanks for the info. In looking through the preferences, it says that my photoshop is using 50% of my available memory - I have 697mb available, so I would think that I shouldn't be too low on memory? Should I up this number? Also, What resolution do you typically work in? What's the difference between screen resolution and print resolution? If you were working in 300dpi that lizard started life out as roughly 2x3" and then enlarged to 9X5"? Or is there no need to change the "resolution" under "Image size" to anything greater than 72dpi? Maybe I have my settings way too large? Thanks for answering all my annoying questions

Divian, no, I did it completely in Photoshop after scanning a pencil sketch. It didn't touch Illustrator at all. Photoshop has paths, too, you know. ;)

Sokol, the lizard was at around 100 dpi at 5" x 9" if I remember right.

Ok thanks, do you think 100dpi is high enough?

Truthfully? I would have used a higher dpi than 100 if I had the processor speed and RAM, but I'm on a four- or five-year-old computer, so I was pretty much forced to find a way to do my art at a lower res. I suggest you use the highest resolution that you can without slowing down your computer so much that you can't work. :)

NO! Sometimes for poster work 200 dpi is enough, but never that low as 100. The exeption would be if the end result gets printed on some inkjet system, which can yield pretty good results from 100 dpi. 300 dpi is what you need for sharp reproduction in print. In pixels, for a 11"x17" image that means 3300 x 5100 pixels in document size. The 'resolution' is about how much pixel information goes into one square inch. For print that has to be much higher than for monitor reproduction. Because you mention the extremely large brush, I remember a mistake I made a couple of time. Look if you, accidentally, did not set the resolution in pixels per cm. That's a whole lot more than per inch... Photoshop can never have enough RAM, but the processor speed of your PC is equally important when working with this serious image sizes. Documents can easily need more than 1 Gigibyte of space (five times the document size in hard disc space), so you have to have that too. That's why Photoshop professionals always want bigger, better, faster machines. It is never enough... Good luck!

It sounds like there's not much of a way around it, huh? I guess I'll have to put up with some hesitation on my brush :( I guess the question now is who makes the best computer systems?

DELL

;)
retrocity

I do not agree, but let's keep the peace. Today is a big day in The Netherlands. In the European Soccer Competition the national team will play agains our arch enemy Germany. So I keep my energy for that (hey! I already changed a tire this morning!)

lol@ hoof!

let us know who wins!

what! you want i should say MAC???

:)
retrocity

a 100 dpi 12" document ( 1,200 pixels )
.. . enlarged to
a 300 dpi 12" document ( 3,600 pixels )

PS will guess 2,400 pixels of information, the print outs will be one that is pixelated and one that is blured.

compared to

a 1200 pixel document @ 100dpi ( 12" print out )
a 1200 pixel document @ 300dpi ( 4" print out)
(only loss of detail is in print out size)

as Aprilgem says " Using paths would probably be the best method " (for increasing the size of, lets say a vector lizard *nice examples , good work *) I agree , they re-size well in PS ...
Vector images made in and edited in, vector programs, don't have pixels (hopefully), thus take up less memory.
but still ....
in PhotoShop, this vector information is in a PIXEL edditing program.

it's the amount of pixels in the image that defines the file size, not necessarily the DPI.

Message edited on: 06/16/2004 20:07

Message edited on: 06/16/2004 20:09

But when you import your pixel illustrations in a lay out program like Quark XPress (I am not 100% about InDesign's handling of size/resolution info), the size can fool you, because that program takes the given dimensions in inches in consideration. So you have to take care yourself of the right amount of pixels per inch. You can make a illustration sized 20" with a resolution of 1 pixel per inch, but it will never look any good. You can change the resolution in Photoshop without changing the pixel size of the document by unchecking the box 'calculate new image pixels' (or something similar, I have a localized version). If you increase the resolution per inch, the size will shrink, but when you set it to 300 dpi, you can immediatly see how large you can use that particular image for print. Recent versions of Illustrator (the vector app) do actually have more and more 'pixel'functions on board (like drop shadows), for which you have to change the resolution to 300 dpi too. I recently found out...

The English version calls the option you need to deselect "Resample Image"

Hmm . . . OK, I've looked at that, but basically it just enlarges the images or shrinks the image based on whe DPI I put in. I guess the main issue I have is that at 20x10" at 300 dpi my larger airbrush stokes have hesitation before actually showing up on the screen. I guess there really isn't much of a way around it, excpet for maybe path, (but I have never used them before).

I agree hoof when our Pixels go into vector programs, and page lay-out programs image resolution needs consistancy, acording to out put requirements ( lines per inch / half-tone screen resolution in print production.) but.. i'm on of those people who save vector files as EPS. save Photoshop files as Tiff ( with Clipping paths sometimes) then I go into the page layout and insert the images into the boxes.. then insert the text into text boxes( needing at least three applications) it would save some time to just make an illustrator file, and imput the pictures there, with the correct imposistion... I've forgoten why some suggest not do it that way. we are the juglers in this digital circus aren't we... (?) ---------- one of the options is not vewing a document at 100 % because basicly your looking at a your image at he same resolution as your monitor, there is the option of * view - print size * with your Ruler's turned on you can faily quickly understand it's dimentions (in inches ) a image that is not re-sampled for example a 100 dpi , 12x 12 inch image - increased to 300 dpi will print out to be 4x4 inches , I think the file size in MB, will basicly be the same. --- to answer the initial question.. in photoshop - it's the amount of pixels. for example a 100 dpi 12"x12" document will have 1,440,000 pixels. a 300 dpi 12"x12" document will have 12,960,000 pixels. guess which takes up more memory? it uses up ram to display the pixels and to diplay the brush... and other things. this is basicly why it's slowing down the painting / rendering process