Obsessive About Color: Endura Kodak Professional Paper

Designing photographic products – films and papers – for professional photographers and finishing labs requires almost obsessive attention to detail. Professional photographers take care to capture the nuance of the subject and scene: flesh tones need to be precise, backgrounds range from neutral screens to indoor and nature settings with vibrant colors, deep shadows, and important detail. Professional labs take care in handling, processing and scanning the film, and in making the final prints. All this made the task facing the Kodak development teams daunting. Their challenge: take the market leading professional papers and make them better in terms of both print life and color. Often these two elements are on opposite sides of the balance sheet: precise color might have to be sacrificed for more stable dyes. An additional challenge was that the paper had to perform equally well as part of both a digital and the traditional optical workflow in the lab.

Two years and several weary patent attorneys later, the research team delivered the critical tone scale necessary for the professional marketplace in the new, highly stable Endura family of papers. Clean highlights with excellent detail are important for wedding dresses and high-key scenes. That translates into the need for excellent performance in the lower scale of the color curve. The papers also have to reproduce deep, rich blacks while maintaining shadow detail in the drape of the tuxedo fabric and the background requiring a curve with strong upper scale performance. Photographic papers designed for these kinds of scenes must consistently reproduce exceptionally high quality images from a photographically demanding scene. Trade tests and initial customer response from around the world have confirmed that the new papers deliver consistently high quality results with flesh and tone-scale performance that sets the standard for the professional marketplace.

One key technology proved to be Kodak’s patented multiple digital dopant (MDD) emulsion technology that allows customers to use the Endura products in both optical and digital printers. This emulsion’s reciprocity performance allows the lab more flexibility by simplifying inventories and workflow, enabling the lab to buy and store a single paper to cover both optical and digital needs.

While most professional portraits originate on color negative film, increasingly the negatives are scanned to create a digital file. Digital cameras are also more widely used. Given the growing presence of the digital files within professional labs and the workflow advantages offered by a digital negative, Kodak designers applied MDD to optimize the new Endura family of papers for both optical and digital printing, enabling the silver halide grains in the paper to efficiently capture light at both very high intensities/short exposure times and very low intensities/long exposure times. This dopant technology generates emulsion reciprocity performance that delivers optimal print performance across an amazing 32-stop printer exposure range from 50 nanoseconds with laser printers through 10 minutes of exposure time on an optical enlarger. . The digital dopant also improves the reciprocity performance of intermittent digital exposing devices such as CRT printers or LED printers. These papers can be used over a broad print engine range from traditional optical enlargers and printers to CRT, LED, and laser print devices. They are also optimized to deliver excellent text characteristics with minimal fringing in digital devices.

Figure 1 shows the reciprocity performance of Kodak Professional Supra Endura paper exposed at 0.000001 sec with a laser compared to optical exposure made at 0.40 sec exposure time.

In addition, the papers’ MDD technology gives the lab more flexibility by simplifying inventories and workflow. Print matching between digital and optical printers is much easier because it is the same paper.

Professional photographers and their clients expect and demand that their pictures exhibit excellent flesh-tones, color reproduction, and neutral performance. Platform coupler technology was used as a baseline but the dye spectra had to be optimized to the precise needs of specific kinds of scenes, thereby satisfying the professional photographer’s high standards for image quality. The Endura papers incorporate three new image-forming couplers that yield dyes with excellent image permanence. These dyes incorporate dual-layer coupler blending technology (CBT) in the cyan and magenta layers.

The cyan layer features a blend of two cyan couplers that produce dyes with both excellent thermal stability and balanced absorption properties. This blend of cyan image dyes result in a single optimized cyan image dye spectrum. The magenta layer is a carefully optimized blend of couplers resulting in a dye spectrum that delivers pleasing flesh tone reproduction and improved background neutrality, especially when balanced on flesh.

The dual layer CBT results in more colorful blues and greens. CBT is critical in producing real-life pleasing flesh-tones. Caucasian, African American, and Asian flesh tones are reproduced with a soft gradation from highlights to shadows. The optimized dye spectra built through CBT produce customer-preferred flesh tones while maintaining neutral tones throughout the scale. This technology optimizes flesh reproduction by removing both harsh highlights and shadows in the flesh tones. Low color saturation for natural flesh tones is also important to professional photographers and is a key element resulting from CBT. Dual-layer CBT enables excellent flesh reproduction performance for optical images from color negative films or for digital images printed onto Endura papers.

Figure 2 illustrates the image dye spectra differences between the current Kodak professional Portra/Supra papers and the new Endura papers featuring blended (CBT) cyan and magenta layer imaging chemistry. The dotted line illustrates the current Supra paper image dye spectra and the solid lines show the CBT-optimized image dye spectra incorporated into Endura Papers.

Figure 2 CBT Dye Spectra of Kodak Professional Supra and Supra Endura papers

The new dye set state-of-the-art for image stability, with a display of over 100 years in a typical home environment.  And the new cyan and yellow image dyes significantly improve the thermal image permanence for prints kept in the dark such as wedding albums etc. . Prints made on these papers will last more than 200 years before noticeable fading takes place in common album storage conditions.

A great look that lasts a long time – cool Kodak technology for the 21^st-century professional labs, professional photographers, and their customers.