difference in inkjet vs traditional printing??

[clay_rodman1]

Hi everyone,

I thought I had this all figured out long ago, but the more I read

the more confused I become. I'm no stranger to the darkroom, so when

papers came out that people used on inkjet printers to print their

digital images that took some getting used to. I had to accept that

people called these papers that held ink "photo paper", which to me

was wrong. Anyway, now I read somewhere that when you take your

digital image, in whatever form, to a lab, they print on "real" photo

paper, but how can that be? So here are the questions:

 

1. When taking a digital image to a lab, what type of paper is used

and how does the image get onto the paper?

 

2. In regular traditional film photography, do labs transfer the

image to digital first by scanning the negative and then print, and if

so, how?(I had assumed that no lab used an enlarger anymore and always

processed the film, scanned the negatives, and then printed from a

digital image, but now when I think about this, how is this done? I'm

used to using an enlarger when I used to do BW photography?)

 

As you can tell I'm really confused. Any answers would really make my

day because this topic is driving me crazy. Thanks.

 

Clay R.

[johnclinch]

As I understand it the image is painted onto the light sensitive paper by shining light onto it.

 

how I don't know?

 

An image focused from a large CRT?

rasta scanning 3 leds (RGB)?

scanning a 1 pixel wide LCD screen over the paper?

 

then the paper is developed

 

sorry that doesn't really help

 

its a great question that I've been mulling over for ages

[alan_olander1664878205]

The negative or transparency is scanned and printed onto photopaper, such as Fuji Crystal Archive, using a laser. I don't know the exact details, but that is one method of digital printing.

[david_rosenbloom]

There are several machines. LightJet and Durst Lambda are what my lab uses. They image onto photo sensitive paper and process wet like a tradtional photo. (kind of)

 

I have been very happy with my Epson 9600. Metarisim is a problem (density shift at angled viewing) but the new 9800 is supposed to improve there.

[steve_swinehart]

With color images, you can use machines like a Fuji Frontier or a LightJet. These machines take digital images and print them to standard color photo paper using either LED's or lasers as the light source. You can load the machines with any type of color roll photographic paper. Most Frontiers are loaded with a Fuji paper (generally Crystal Archive). LightJets can be loaded with any type of paper. A local lab that I use will print on either Fuji Crystal Archive or the Kodak Metallic paper.

 

For black and white work, DeVere makes the 504DS enlarger. This is an enlarger with a projection LCD built into it. The digital file is projected by the LCD onto ANY standard black and white photo paper.

 

With chromogenic black and white films (processed in C-41 color chemicals) many of the digital printing machines have settings to allow printing this B&W film onto standard color paper.

 

Inkjet printing is a totally different method of printing. You can use specially prepared inkjet "photo papers" that have glossy or pearl surfaces to mimic standard photo papers. Or, you can use matte papers, canvas, or even watercolor papers.

 

The inkjet papers are specialty papers that have in receiver layers built into them to limit ink spread (dot gain in regular offset printing) where the little spot of ink gains in size because it diffuses out into the paper fibers.

 

These are not traditional photo papers as such because they do not have a metal + halide (silver bromide, silver chloride, platinum, etc.) as part of an emulsion coating. They are called photo papers because they are generally used to print photographs. Of course, you can print ANY type of digital image onto them.

 

I have an Epson 9600 printer and print both photos and digital art onto a variety of papers. One of my clients does digital artwork that looks much like serigraphs which he chooses to have printed on a Moab Entrada paper - the same paper I use to print my own photographs.

[steve_swinehart]

Metarisim is a problem (density shift at angled viewing)"

This IS NOT metamerism. Metamerism is a color perception problem. It is when two objects match in color under some lighting conditions but not others. This is a color comparison between two colors. It is a problem found in every industry using color pigments or dyes.

 

Cloths are a big example where the color shifts under different lighting. You know, the shirt and pants looked great together in the store, then you looked at them under different lighting at home or outdoors and suddenly the colors didn't complement each other.

 

With inkjet printing you have "pseudo metamerism" which is a bit different. You notice a single color changes under different lighting. Since this is not a color comparison between two colors it is not truly metamerism. This has a lot to do with the color rendering index (CRI) rating of the light source as much as the ink itself.

 

Another inkjet problem is gloss differential. This is sometimes called "bronzing." It is a problem with pigment inks and not dye based inks. Gloss differential happens on glossy paper with dark colors (blacks, dark blue, etc.) printed with pigment inks because there is a heavy coating of ink in the dark areas. The pigments do not penetrate the gloss coating of the paper, so the dark colors/heavy pigment areas look matte while other areas of the print look glossy.

 

Epson has a strategy with their pigment inks where they are encapsulated into very small ball shaped containers of ink. You have to think of the ink pigment contained in a very, very small (smaller than the diameter of a human hair) capsule. In effect, the ink is a wet carrier with billions of tiny balls suspended in it.

 

This does two things. First the ink flows through the heads better, and second it helps a great deal with head clogging as their are no pigments to dry out and stick to the print heads.

 

When you clean the heads on Epson printers using Ultrachrome inks, you are really just flushing out some of the carrier medium + tiny ink balls, not jagged pigment pieces that really stick to the head interior and are very difficult to flush out.

 

When the ink is "shot" onto the paper by the print head the capsules break allowing the ink to be released onto the paper. The capsule coating fragments float to the surface of the paper making a coating over the ink. This usually takes 3-4 hours and you can see the image change over that period of time. With the new Ultrachrome inks to be released with the X800 series printers, the capsules will be glossier, which will help with gloss differential.

 

The inks pigments have also been reformulated to reduce color shifts under different light sources.