What is Soft Proof?

​​​​​​​At our printing house POINT CZ, we often encounter uncertainties regarding the term "Soft Proof" or "PDF Proof." Let’s clarify what this key function in industrial printing production serves and why it is important.

How Does Soft Proof Work?

Soft proof is a "software proof" of correct processing on the RIP (Raster Image Processor). The output of the RIP is a bitmap (raster), from which the Soft Proof is created. This bitmap is further processed, and printing dots are calculated for individual color plates. Based on these, the printing plates are produced using a CTP (Computer-to-Plate) exposure unit.

What is Soft Proof Used For?

Soft proof does not replace quality control of input data or proofreading. It is the final technical check before printing that reveals possible errors in RIP data processing, such as incorrect interpretation of transparencies, font processing issues, or missing images due to hidden errors in printing data. Soft proof is ideal for clients who cannot or do not want to be physically present at the print run startup but want to ensure that the final print will meet expectations.

The only alternative to Soft Proof is a real sample print or personal presence during the print run startup. However, these methods are more costly and time-consuming, although they offer the advantage of real color display on the specific material and allow for potential color correction directly during printing.

Soft Proof Does Not Replace Graphic Proofreading

Proofreading is performed before sending data to the printer and takes place between the graphic designer and the customer. The printing house works only with approved data to efficiently plan high-volume printing and guarantee the delivery deadline.

Product Specification Before Printing

Before placing an order for printing, it is necessary to specify the product. This specification is used for preparing the offer, checking input data, and creating the Soft Proof. Soft Proof does not serve for finalizing order parameters.

Historical Alternative: "Proof Sheets"

In the past, our printing house used so-called "proof sheets" – printed sheets in the lowest quality on the cheapest paper. These proof sheets were checked in the printing house or sent to the customer by mail. Today, Soft Proof replaces this function in a higher-quality digital form.

Historically, proof sheets were used to check whether the typesetter correctly arranged the letters and additional components (lines, ornaments, engravings, etc.). From the typesetting, a manual control print – colloquially known as a "proof sheet" – was then made.

POINT CZ specializes in industrial printing production, including calendar printing, high-volume printing, and packaging production. Soft Proof is an essential part of the entire process, helping to ensure precise results for every order. Do you need to place a print or packaging order? Contact our specialists.

Printing Terminology Used:

Raster Image Processor (RIP)
RIP converts digital files (PDF, PostScript) into a bitmap for printing. It can be software or hardware-based. Processing includes interpretation, rendering, and rasterization.

Bitmap
Bitmap graphics are composed of pixels with defined colors (formats: TIFF, BMP, PNG, JPEG). Higher resolution means more detail and larger file size. Unlike vector graphics, it operates on a fixed grid of points.

Proof Print
A test print version to verify colors and content. It can be printed (faithful material simulation) or software-based (digital display on a calibrated monitor). Goal: eliminating errors before printing.

Halftones
Printing continuous tones using small dots of varying sizes (AM screening) or distribution (FM screening). The human eye perceives dots as smooth transitions, which is the basis of CMYK printing.

CTP (Computer-to-Plate)
Direct laser imaging of the printing plate without the need for film. Speeds up the printing process, improves quality, and reduces costs.

Author of the article: Ondřej Srstka, Data Control POINT CZ