How to control the color of digital printing
How can we get a good color reproduction effect on the digital printing machine? "This is a delicate balancing problem," said Mr. owshi, according to Doug polark, a technical expert in the uarco printing department, who chose the seven tips of the universal tension machine, "In order to explain the problem of toner on paper, I want clients to recall a game that the older generation of children often play, that is, rub the balloon on their hair, and then stick it to the wall. This game is easier to realize in dry weather than in summer, and the same is true of toner falling."
according to the point of view of the printing personnel and the personnel of the production center, to obtain good and stable colors from the digital printing machine, we need to have corresponding tools and experience at the same time. None of them believe that color control and calibration can achieve a fully automatic process
"we still need to have a good eye," Mr. Marc Orchant is the printing manager of Subia, a digital printing company. He said, "moreover, when we deal with toner and ink, we should also consider the new color gamut." A chrompress user, Mr. Orchant, said that Subia used the company's most stable products - such as high-resolution films plus high-quality contract samples for this work
then, the technician created several test files, which included some colors and textures that were difficult to copy (such as gemstones, skin color, neutral gray, etc.)
finally, after linearizing the equipment, they calibrated the color scale under white light
now, the manufacturer has provided the company with many tools to help them solve this problem. Agfa now offers a "second version" of three types of Chromapress consumable materials (toner, developer and image drum), said Agfa's product manager. Agfa stressed that in order to avoid the problem of developer expiration, they have a regular retention procedure
moreover, the Chromapress device can perform color registration and color density adjustment through the server, and it can be adjusted randomly, and the adjustment can occur on various color printing parts
the thoroughness of this work, I hope we can get results from IBM. Mr. Chris Parker, business manager of IBM's color printer products, said that the company spent nearly a year testing 10 of the same Xeikon printers before releasing their infocolor 70 products, "We try our best to find the biggest change area in the display effect between the operator and the equipment. The results clearly show that the problems caused by calibration, printing materials, or any other change factors are much smaller than those caused only by the actions of the operator. The software may only change in the registration problem, and many operators may produce several changes, resulting in a lot of waste." Mr. Parker believes that this trend mainly comes from the offset printing experience of operators. "When offset printing, just keep the equipment on until the color on the ladder looks good. But it is not suitable for digital printing machines."
interestingly, Mr. Parker (2) claimed that the problems of color and printer control in digital printing are basically the same as those in offset printing. "For example, for a former offset printer, the adhesion of toner is no different from the ink balance in offset printing. The roller voltage - has a great impact on digital color reproduction, which is a bit like the pressure of a rubber roller. The LED exposure on a digital printer can be compared with the plate exposure," he suggested
ibm's long-term workflow analysis of infocolor 70 before use makes Agfa company include fully automatic density measurement technology in their products. This product is also equipped with a built-in heating head (to improve humidity and temperature control) and a Gretag densimeter. The latter equipment is connected to the server and can prompt the color value of the encoded live parts as long as necessary
in addition, infocolor 70 also provides: swop and European standard extended color lookup table for automatic color matchingGeorge Willock, President of colorstream, is very proficient in infocolor. This digital market development company has sold 650000 copies of programs in 90 days Mr. Willock said that colorstream users need a user solution for color management. Unlike the standard color tools that load infocolor devices, the company (and users) uses the optical product of color partnership to achieve high-quality Remote Proofing and soft proofing through ISDN or T1 lines
if the color control of offset printing is a goal, indigo users are eager to mention that their printing presses (print 1000+ and omnius) do the same
"it can get the best color quality," asserted Charlotte Krebs, indigo branch manager of Hollis digital. "It is worth mentioning that Indigo's technology is unique in digital printing machines. It uses electronic inks with liquid pigments to obtain high gloss, offset like effects."Hollis company is a digital printing company with 25 employees. Mr. Krebs said that the biggest difficulty now is to match the color reproduction of the printed matter printed in the early stage or reprinted. The company retains samples of all live parts to help with visual matching. "Sometimes, our operators can even remember exactly how a living piece is printed," Mr. Krebs commented
however, more systematically, Krebs' employees have formed some operating procedures: daily calibration of the equipment, its own color code control page, and careful density measurement technology (to ensure that the equipment will not be over compensated)
including material recommendation, structural function design and on-site process guidance. If the color problem still exists, output a sample, "we will adjust it on the printing machine". If this still doesn't work, Mr. Krebs said that they will go back to Photoshop to adjust the file. It is rarely a mechanical problem, so it is best to leave it to the printer to solve it, he suggested
with the output of Xeikon based equipment, if it cannot be maintained correctly, the developer may fail, just like the wear of plates in indiog's production process (voltage will decline). Mike chiricuzio, an old user of E-print 1000 and general manager of sequel Inc., said he was glad to have a new upgrade in his front-end software, which can synchronize with the life of the printing plate and automatically calibrate the changes
in addition, for more than 700 customers of sequel, indigo system can store the density setting of each live part to ensure the stability of color
for most samples processed by digital printers, climate control is the key
sequel company (where the humidity is 2%) has installed a humidity regulator near the printing press, and even cooperated with the air conditioning system in the factory, but the gap is decreasing
in order to get better colors, Mr. chiricuzio expects the emergence of an updated version of indigo ink system - electroink III. he hopes that this system will provide an effect that better matches the gloss of the paper used by sequel
in the final analysis, digital printers did not agree on the level of color reproduction they could achieve. On the one hand, indigo users like Mr. Krebs like to show off the copied 2point text to their customers under a magnifying glass, and say, "this is impossible in toner based printing technology."
information source: must win