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07/17/2002 11:43:41 AM · #1 |
I can't really take the picture in tiff because I go from 90 pictures to 20 in tiff. And it takes me lots of shots. I guess I could if I were just after the one picture.
Tim |
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07/17/2002 11:51:35 AM · #2 |
5"x7", I think, at maximum quality. I think you should be able to interpolate the image up to 8"x10" though without too much loss of sharpness (if you don't crop too much). It's not going to be the same quality as a 5 mp 8"x10" if you look at it with a magnifying glass, but it won't be unacceptable for normal viewing.
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07/17/2002 12:02:11 PM · #3 |
2.1 megapixels is a 1600x1200 pixel image. You could print as follows:
22" x 16" at 72 dpi
16" x 12" at 100 dpi
10" x 8" at 150 dpi
8" x 6" at 200 dpi (minimum resolution for good photo quality)
5.5" x 4" at 300 dpi
The higher resolution you want to print, the smaller the print size will be. The size you can print and get a good quality print depends on more than just the pixel size of the image. If you want a photo quality print on high gloss photo paper, you definitely need the higher resolution. If you are going to print on matte paper, you can get a really nice quality print with a lower resolution.
I have printed a few 100 dpi images on the inkjet canvas paper that look really great...
experiement.. try things.. see what you like :)
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07/17/2002 12:14:48 PM · #4 |
Originally posted by jmsetzler:
The higher resolution you want to print, the smaller the print size will be.
No comprendo.
i.e. sorry about my "slow learning curve" ;) but, how does this happen?
* This message has been edited by the author on 7/17/2002 12:14:41 PM.
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07/17/2002 12:18:52 PM · #5 |
Originally posted by Karen Bryan:
Originally posted by jmsetzler:
[i]The higher resolution you want to print, the smaller the print size will be.
No comprendo.
i.e. sorry about my "slow learning curve" ;) but, how does this happen?
[/i]
Your image is a fixed number of pixels in length and width. The 2.1 megapixel image is 1600 wide by 1200 tall. When you view this image at full size on your screen, it is displayed at 72 dots per inch. 72 dots per inch on the printer is not good resolution. To get good photo quality, you need a minimum of 200 dots per inch to the printer. 1600 divided by 200 = 8 inches. So, to get a photo quality print from a 2.1 megapixel image, the maximum width of the image would be approximately 8" at 200 dots per inch. More dots per inch to the printer would further reduce the 8" to something less...
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07/17/2002 12:22:43 PM · #6 |
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07/17/2002 12:33:23 PM · #7 |
I'm not too good at explaining this :))
Imagine a rectangle that is made up of dots. The dots are colored and have spaces between them. The colored dots make up a picture of some sort, like our digital photographs. The amount of space in between these dots defines the 'print resolution' of our image. If we increase the amount of space between our dots, we have a larger picture, but there are less dots per inch. If we decrease the amount of space between these dots, we have a smaller image with more dots per inch.
We are not adding or subtracting any dots from our image as we change the spacing between the dots.
Does this work any better?
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07/17/2002 12:55:08 PM · #8 |
I'm no good with this. Aren't all digital pics 72 dpi? Even if you shoot them in .tif mode? I can't understand this and I guess I basically need a picture drawn out for me. When I scan photos, I scan them at 300 dpi usually. Sometimes I even scan them higher if I'm not sure how much room I'm going to have to size down to. I was always taught that it's okay to size the photo down but never try to size it up. Because you can't add pixels...I understand that. When I get digital photos at work, (on a disk, showroom photos of furniture) I always size them down because they are the large size like you said...usually around 22 inches. But I can never make them look decent enough. Because of the quantity that they shoot, (around 200) and the amount of time I have to turn them around and print them (around 1 week), they don't usually shoot them in .tif mode. It's hard for me to explain without showing you what I do but somewhere in the process, I lose color and sharpness. Help!!
If it's nothing more than telling me what settings to tell my boss to use when she shoots these things....I could really use the info. She's not a professional and this is basically done to save the company money. We eventually have professional photography shot but these visuals are for our sales force, to let them give the customers at least an idea of what the new furniture lines look like. We have an Olympus camera but I'll have to check to make sure what model it is.
Karen |
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07/17/2002 01:01:22 PM · #9 |
Your computer displays images at 72dpi. I don't know whats going on with your downsizing.. are you resizing or resampling? These are often confused but they are not the same thing...
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07/17/2002 01:08:01 PM · #10 |
Originally posted by jmsetzler:
Your computer displays images at 72dpi. I don't know whats going on with your downsizing.. are you resizing or resampling? These are often confused but they are not the same thing...
I think my problem is, I'm resizing them (down) but then putting them on a template that is 300dpi. So I guess that's where my color loss is coming from. If I could just put them online for the sales force to see, that would be a lot easier...but not all of them have laptops. I'm totally screwed up...it's not that the photos look that bad, but we're talking furniture here..colors and finishes have to at least look somewhat close to the product. I usually spend a weekend color correcting on each individual photo. |
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07/17/2002 01:12:28 PM · #11 |
Hey KD;
You are correct, most of the digital stuff out of the camera is DISPLAYED at 72 dpi..but the PHYSICAL SIZE and RESOLUTION of a print can change to however you want to spread those pixels.
For instance, just for ease and discussion. My Canon G2 shoots it''s largest JPEG image at 2272 pixels x 1704 pixels. I can squeeze or stretch those pixels to fit any size I want.
At 72 dpi I can make it 31.5 inches x 23.66 inches. Not a bad poster size for school plays or other general purpose large graphic applications. Or...I can make it 7.5 inches x 5.69 inches (my typical choice for glossy photo prints) for nice presentation photos.
BTW...Newspapers can only print at 72 dpi I believe..maybe 120 dpi so a FAST camera with a nice lense at about 2.5 megapixel resolution is all you need for nice newspaper work.
The Olympus stuff are great choices for mid price newpaper work. Or a very nice Nikon D1h. the lens and speed is all important.
* This message has been edited by the author on 7/17/2002 1:16:58 PM. |
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07/17/2002 01:17:54 PM · #12 |
So when I''m taking that 72 dpi image and placing it onto a 300 dpi template in PhotoShop...it''s basically stretching the pixels? That''s why I get a color change? Arrghhhhh...why can''t they just give me a photo to work with??? I hate technology sometimes.
ok...dpi is dots per inch and ppi is pixels per inch....am I even using the wrong terminology?
* This message has been edited by the author on 7/17/2002 1:21:05 PM. |
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07/17/2002 01:22:13 PM · #13 |
this is not hard to correct... I can give u instructions on that when i get back in front of a machine that has photoshop on it..
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07/17/2002 01:30:01 PM · #14 |
Originally posted by KDJohnson:
So when I''m taking that 72 dpi image and placing it onto a 300 dpi template in PhotoShop...it''s basically stretching the pixels? That''s why I get a color change? Arrghhhhh...why can''t they just give me a photo to work with??? I hate technology sometimes.
ok...dpi is dots per inch and ppi is pixels per inch....am I even using the wrong terminology
Depends on how many pixels you have and how large you are making your template.
Whatever program you are using (photoshop or paintshop pro the 2 most common) will tell you the size of the unaltered, right-from-your-camera image size in pixels like my 2272 x 1704 example for the G2.
When my Photoshop program looks at the photo directly from the camera it is 33 inches by 24 inches at 72 dots per inch. If I were to simply tell photoshop.."O.K... give me a 300 dpi image ..click"...It would automatically size it to 300 dpi and I would be looking at a 7.5 inch x 5.66 inch picture on my screen now instead of a 33 x 24.
In this scenario the pixels were squished closer together..all the pixels (2272 x 1704) are still there, just smaller and closer together.
* This message has been edited by the author on 7/17/2002 1:33:59 PM. |
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07/17/2002 01:51:46 PM · #15 |
Oh My God....I get it....and you know what else???? I WAS resampling...oh wow.....this is incredible. I can't believe I didn't know that.....thank you guys SOOOOOOOOoooooo much. I feel like crying....market photos are going to be so good this year..lol. Thank you...thank you thank you thank you thank you!!!!!!
Karen :) (Happy Camper) |
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07/17/2002 01:52:44 PM · #16 |
| I just have to say thank you again.....this whole site ROCKS!!! |
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07/17/2002 01:58:34 PM · #17 |
So, what'd you do to correct your problem?
Drew |
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07/17/2002 02:04:49 PM · #18 |
Originally posted by drewmedia:
So, what'd you do to correct your problem?
Drew
When I brought the 72 dpi image up, I was resampling it when I resized it...changing the number of pixels...adding ....basically adding black right,? because you can't add pixels and get a good print. I clicked the box on the resample to deselect it and made it 300 dpi....I haven't tried to print but I'm assuming this was my problem...right?? brb..I'll go print it...
well..ok....maybe that didn't fix my problem.....it still looks pixelated when I print it....
I need a drawing.... |
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07/17/2002 02:09:41 PM · #19 |
Ok...I finally got it....I think.
My image is 436 x 587 pixels, print size 6.056 x 8.153, resolution 72 ppi.
I deselect the resample image box and bring the resolution up to 300 ppi. Then I click back on resample image and bring it back up to the 6 x 8 inch size I need...It prints great.....so is this what I need to do???
* This message has been edited by the author on 7/17/2002 2:09:47 PM. |
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07/17/2002 02:11:10 PM · #20 |
Karen;
What are the pixel dimensions on the photo you are working with? And what size are you trying to pring to? |
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07/17/2002 02:20:22 PM · #21 |
I might as well add to the confusion. When you open up your image in Photoshop and go to resize it or to change the dpi it is important to take note of the width and height in pixels that the original image contains. If the pixel dimension were 1600 x 1200 then you need to make sure that it 'still' says at least that 'after' you have inputed the proper dpi and output size unless you purposely require something less. Dpi or ppi, simply is the number of dots or pixels in an inch, and nothing more. The actual pixel dimension, 1600 x 1200 for example, is the most important bit of information because that is your actual data. If that gets reduced by accident then you have thrown out important information that can't be recovered. This is one of the most common mistakes I see people make, they accidently do something wrong when they change the image size and greatly reduce the pixel dimensions to an unusable number and then wonder what happened when they print the awful picture.
Tim J
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07/17/2002 02:29:55 PM · #22 |
But wait, there's more. A tif and the highest quality jpeg will still have the same number of pixels. The file size in the jpeg is reduced only because color information is tossed out which is barely noticeable. There is very little reason to use tifs because they are nearly, and in most cases, absolutely indistinguishable from the highest quality jpegs.
Tim J
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07/17/2002 03:02:09 PM · #23 |
There's a very thourough explanation of the above topic at the Luminous Landscape. It helped me figure this all out, at least. It has Photoshop illustrations and all, too. I really recommend reading slowly and maybe even a few times to really get these concepts down, cause they're crucial to being able to print and even to resize for website submissions.
I dunno if there's some sort of list of links for an eventual link page, but I think this one would be a good one to include if there is.
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07/17/2002 03:14:51 PM · #24 |
Kim, there's a suggestion area in the tutorial section for other site tutorials.
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07/17/2002 03:18:14 PM · #25 |
There are three or four separate things all referred to as dpi!
FILES:
ppi = pixels per inch. The basic unit of data in the computer file, defined by a binary value of (usually) 1-24 bits/pixel.
SCANNERS:
dpi = dots per inch. The number of physical light sensors in each inch of the scanner array. Can be adjusted up or down in software either during the scan or afterwards in the editing program.
OUTPUT DEVICES:
dpi = dots per inch. The smallest physical mark the printer can make on the media. A dot-matrix printer is usually 72/in. Most office laser printers make a spot from 300-1200/inch. High-resolution imagesetters and film recorders usually put a laser spot between 1200-4000/inch. Most modern inkjet and bubblejet printers make a spot between 720-2880/inch.
REPLICATORS/PRINTING:
LPI = Lines per Inch.
When photos are reproduced by offset printing or on laser printers, the image must be broken into "halftone dots." This is because printing presses are binary: ink/no ink. They cannot print ink at 20% opacity. For the last 100+ years or so, this problem has been worked around by breaking the picture into tiny dots. Big dots close together look like a dark color, small dots scattered look lighter. If viewed from far enough away, the eye cannot resolve the individual dots, and perceives a shade of gray (or color).
Each DOT's value is determined by averaging the values of the PIXELS which underlie it. There will typically be 4 PIXELS comprising each DOT, determined by the ratio of the LPI (screen) value and the PPI value of the file). This is why a photo may print perfectly on a laser or inkjet, but appear pixelized if printed to film for a magazine. The ideal is to have two pixels in your file for each halftone dot you want to print. Newspapers typically print at 65-100 LPI, so your files need only be 130-200 ppi. But a magazine printing a 150 LPI screen needs a file of 300 ppi.
There is also a relationship between the DPI (spot size) of the output device and the halftone screen (LPI); although the VALUE of the halftone dot is determined by the pixels, the physical halftone DOT is actually made by the laser (or ink) spots hitting the paper or film -- the more SPOTS available to build each DOT, the more accurately the DOT's value can be reproduced. That's why you can print a good-looking photo on a laser printer at 85 LPI, but send it at 150 LPI and it will appear posterized. On a typical 600 dpi office laser, an 85 LPI has each dot made up of about 1-49* laser spots, so you have about 50 shades of gray available. At 150 LPI however, each dot can be made up of only 1-16 laser spots, leading to a posterized look.
* 600/85 = 7; 7x7=49
600/150 = 4; 4x4=16
Photographic printers (lasers imaging photo paper) seem to be standardized on 300 ppi for optimum quality, 200 ppi for acceptable, and 100 at a minimum.
RESAMPLING:
Photoshop (and I assume all programs) either create or discard pixels by computing some average of the surrounding pixels. "Bicubic" is the Photoshop standard -- I forget why they still include the other modes.
Pixels are exactly like tiny tiles in a mosaic -- they are indivisible units. When you resample UP, the pixels are spread apart, and new ones created to fill in the gaps based on the values of their neighbors. Resampling the file smaller means the values of a few pixels will be averaged into one, and the rest discarded.
I now resample up in Photoshop if I'm going to make a large print, so I can see the effect of the resampling ahead of time, and maybe fix any problems.
BTW: To answer the original question at the top of the thread -- I routinely print up to 8x10 from my 2.1MP Olympus, but I usually crop and border the prints so I don't resample up too much. However, I have resampled about 3 images up to print 16x20 and 20x30" and got (to me) an acceptable result, but they WERE intended for family and not necessarily for public display. I have a "public" folder of about 50 prints prepared for photo output -- send me a note if you want a link to it.
--Paul |
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