........Demand of Dot Proofing or Screen Proofing


Demand of Dot proofing or Screen Proofing

One of the great controversies plaguing the printing industry is the argument over halftone proofs and whether they are truly needed. On the one hand, you have those who say they don¡¯t need halftone proofs: ¡°Why should I? Since I am already getting color approval, all I need is a proof that shows how the color will print.¡± On the other hand, you have those who swear by the halftone proof, claiming they need to be able to predict moire. ¡°I don¡¯t want the client to see an image that is smoother and more detailed than what I can achieve on press,¡± they say.

Most inkjet proofers use error diffused or frequency-modulation technology. The advantage of this is that it produces a smooth, continuous-tone quality. The disadvantage is that this does not replicate halftone screens. Color management systems (CMS) complicate the issue. When remapping the inkjet color gamut, CMS uses additional dots to match the printing press gamut. This is especially true with six-color proofers. While six colors provide a much wider spectrum for matching special colors and different types of presses, it adds colors that are not present in the CMYK rosette.

Luckily, inkjet technology has come a long way. With the right screening technology, and a proofer that can print 1440 x 1440 dpi, dot-for-dot halftone reproduction becomes a reality. It is even possible to achieve dot simulation at 720 dpi, which is sufficient for predicting certain types of moire. Although dot simulation is not an exact representation of the halftone rosette, it more closely represents how the final printed sheet will appear. It can also predict two types of moire?color moire, which results from incorrect screen angles, and subject moire, which is the result of a complex pattern such as a checkered print interfering with the halftone screen.

Dot-for-dot halftone proofs print the details of the screening structure exactly as it will appear on press. The rosette patterns are identical, so all types of moire effect can be accurately predicted. The individual dots on the proof have the same shape, size and color. In addition to a resolution of 1440 dpi to recreate an exact rosette, a proofer must be able to handle multi-density inks and produce ink drops of no more than five picolitres. Furthermore, the RIP must generate the same screen rulings and angles, and interpolate the data in exactly the same way as the platesetter RIP.

Why Dot proofing? Why Screen proofing?
For many years the prepress industry has been looking for a digital proofing solutions to correct errors in pages before final output to film or plate. Most of the digital proofing solutions come with its own PostScript¢âRIP with color management system for small or large format printers. These solutions require the composite PostScript¢â pages to be sent, first to the proofer RIP to produce the digital proof. After a confirmation proof is produced these pages have to be re-sent as a separated PostScript¢â files to a totally different RIP that sends the Hi-Resolution data to a imagesetter or platesetter. This RIPping twice with two different RIPs, generating two totally different results.
Both the ¡®Digital Proof¡¯and the ¡®Final Print¡¯ will definitely not match. Text reflows, font errors,
OPI faults, trapping and other PostScript¢â odd problems are common. This dilemma of two different RIPs is simply overcomed by VisualDot, which uses Hi-Resolution data to the Final Print itself for Dot-proofing. It helps you secure absolute Data integrity of your Halftone Screening in CTP/CTF Delivering screened inkjet proofs with Contract Quality & Assured Data Integrity.

Beyond the Continuous Color Proofing
You can save your Cost and Time by early recognition of Moires and Trapping errors with Dot-for-Dot reproduction. VisualDot is an essential solution in Dot-proofing for the prepress industry.
VISUAL DOT digital screen proofing software is a revolution in Dot-Proofing for the Pre-Press Industry.
Color-accurate continuous proofs are not always sufficient when a real contract proof is required.
In many cases, a proof is needed that not only reproduces color accuracy, but also shows the halftone dot pattern. VisualDot provides the ability to resample high-resolution, pre-separated, screened bitmap plates from the CTP/CTF RIP into a accurate inkjet-printed representation with screen angle, screen ruling and dot shape preserved in their entirety. Halftone proofs are vitally important for identifying problems like Moire artifacts, incorrect trapping settings or interpretation errors in the imagesetter or CTP RIP before plates are exposed or the print process begins.
Halftone proofs help users minimize the cost and time losses resulting from prepress errors.

Continuous Color Proof is NOT enough for continuous proofing purpose itself
Screened DOT proof delivers Contract Quality of proof in color and details as well as screen dots. The prepress industry has long time history and software technology, mechanical/chemical printing technology and optical device technology has been tremendously enhanced so far. However, it is physically difficult to produce exact 'press-look' proof with inkjet printers because of different ink system, microscopic details, characteristics of media and etc. But in most of prepress industry, professionals have developed their own rigid way of continuous color proofing with experienced trials and errors, which cannot be caught up with by any intelligent software technology. However, even professionals have difficulties in producing toned-down color, high-resolution of small fonts and narrow lines of the press in inkjet color proofing. That's the limitation of color proofing without screen dots. VisualDot will deliver the most press-look proof by overcoming the limitation of continuous color proofing. People will get the press-look colors and details in small fonts and narrow lines by simply adding VisualDot to the same continuous color proofing workflow.

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