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photoshop

graphix

New Member
Hello all,
Question when i click new background and make resolution 300 does all the pictures i bring in change to the 300? or how do i bring in a picture the right way for digital printing?
i guess the question is what happens when i choose 300 resolution thanks...
 

oldgoatroper

Roper of Goats. Old ones.
your images will come in to the new image pixel for pixel.

If your imported image is 100x100 pixels, then it will occupy a space of 100x100 pixels in your new image even though your new image may be larger like, say, 300x300 pixels.

Resolution doesn't matter.
 
If I'm understanding you correctly, you are asking what happens to an image that is pasted into a new layer over your background that you have selected as 300 dpi? Everything pasted into your new project will automatically be re-scaled to 300 dpi. But if you are using a low quality image to start with (72 dpi or similar) the conversion, most likely, won't be a smooth one. For any digital imaging you should be using 300 dpi images at the very least. If you have to use lower quality images, I would definitely suggest converting those images to a much higher resolution first, such as 600 dpi, cleaning them up using various tools (gaussian blur works wonders for some images, then just resharpen), then pasting them into your new 300 dpi image. Then you can re-scale it down to fit your image from there.
 

oldgoatroper

Roper of Goats. Old ones.
Sorry, I shouldn't have said that resolution doesn't matter.

It would be more accurate to say that when importing an image into another image (pasting into a new layer), resolution is irrelevant.

Your imported image will be mapped, pixel for pixel, into the space of the host image (or background) and will take on the specified resolution of the host image. No change occurs to the imported image -- it is not scaled, per se -- it is merely re-mapped.
 

graphix

New Member
why is it when i take a pic 8 meg and open it it only shows 72dpi? i can change that to 300 dpi but file dont get better....how would you bump up the dpi or resolution...thanks..
 

Bigdawg

Just Me
First of all... you don't generally need 300 dpi for sign printing. High-end offset printing - yes... digitally printed signs - not really.

When you change the resolution in the "image size" dialogue box, if you have "resample image" clicked on, it will reinterpret the photo to the new dpi affecting quality. If you click that box off, then the image will resize pixel-for-pixel to accommodate the new resolution.

For example, if you have a 14"x8" picture that is 72 dpi and you change the resolution to 300 dpi with the "resample image" box NOT clicked on... your photo will resize to about 3.5 x 2 inches. If you have it clicked on it will stay the same size, but the quality will get worse. So if you have a document that is 300 dpi and you paste that 14"x8", 72 dpi picture into it... it will come in at about 3.5 x 2 inches.

How big are you trying to resize to?
 
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oldgoatroper

Roper of Goats. Old ones.
Keep in mind that the indicated resolution (72dpi, 300dpi, whatever) is only a calculated value based on the number of pixels the image has spread over the number of inches the image has been assigned to cover.

The size of an image or its resolution are only arbitrary assigned values that are both dependent on the absolute number of pixels the image has.

If you change the dpi of an image in PhotoShop without resampling it, all that really happens is that PhotoShop conveniently recalculates a new size for you. Likewise, if you change the size of an image without resampling it, then all that PhotoShop is doing is recalculating a new dpi (resolution). The image itself undergoes no change at all. Not a single pixel is affected.

Resolution or size of an electronic raster image are meaningless by themselves without an express reference to the other. You cannot say that an image is 300 dpi without also saying that is such-and-such a size and vice versa.

However, if you refer to an image's size in pixels (i.e. 3000x2000), that will tell you all you need to know and any size/resolution can be calculated from that.

Usually, any image that is indicated to be 72dpi, simply has had no arbitrary values set for size or resolution, so PhotoShop and other programs show 72dpi as a default.

The best thing you can do over time to really understand this is to largely ignore what resolution an image is and instead, pay much closer attention to what the absolute size in pixels is and how that translates into dpi at the size you want to print it...
 

graphix

New Member
this is the size and don't know what all it means...thanks for helping i just thought 300 dpi would help with print quality picture will be for a 4x2 ft banner..
 

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oldgoatroper

Roper of Goats. Old ones.
Well, there ya go...

Absolute size of your image is 3456x5184 pixels. If you are going to print this image at 100 pixels per inch (ppi), then you could print it at 34.56" x 51.84 inches. Simple as that.

Of course, if you were to print that image at a smaller size, then its ppi would go up correspondingly.

Extra note: though we often say dpi (dots per inch) when referring to digital images, we really should force ourselves into the habit of using pixels per inch (ppi) as that is the proper reference.

Dots per inch (dpi) is really a designator of another property of printing processes which is beyond the scope of this discussion.
 
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