Eurographics Symposium on Rendering 2013 Nicolas Holzschuch and Szymon Rusinkiewicz (Guest Editors) Volume 32 (2013), Number 4 Computational Simulation of Alternative Photographic Processes Jose I. Echevarria 1 Gregg Wilensky 2 Aravind Krishnaswamy 2,3 Byungmoon Kim 2 Diego Gutierrez 1 1 Universidad de Zaragoza, Spain 2 Adobe Systems Inc., USA 3 Google Inc., USA Figure 1: Our image processing pipeline allows the simulation of the craftsmanship and final looks of analog alternative photographic techniques like wet plate collodion (left and center) or cyanotypes (right). The dynamic nature of our fluids-based chemical reactions and the required manual work interaction provide unique results, similar to their analog counterparts and their unique local heterogeneities. The small inset shows the original scene, courtesy of Tracie Tee. Abstract We present a novel computational framework for physically and chemically-based simulations of analog alterna- tive photographic processes. In the real world, these processes allow the creation of very personal and unique depictions due to the combination of the chemicals used, the physical interaction with liquid solutions, and the individual craftsmanship of the artist. Our work focuses not only on achieving similar compelling results, but on the manual process as well, introducing a novel exploratory approach for interactive digital image creation and manipulation. With such an emphasis on the user interaction, our simulations are devised to run on tablet devices; thus we propose the combination of a lightweight data-driven model to simulate the chemical reactions involved, with efficient fluids simulations that modulate them. This combination allows realistic gestures-based user inter- action with constant visual feedback in real-time. Using the proposed framework, we have built two prototypes with different tradeoffs between realism and flexibility, showing its potential to build novel image editing tools. Categories and Subject Descriptors (according to ACM CCS): I.4.0 [Image Processing and Computer Vision]: General—Image processing software 1. Introduction Digital photography brought along powerful, intuitive image editing techniques that allow the user to dramatically change the final look of the image. Some of these techniques are de- signed to mimic the results from analog photography, mainly by means of tone manipulation [GM97, RSSF02, BPD06], or are encapsulated into single-button filters, such as the popu- lar Instagram. It is interesting to see the way the general pub- lic has embraced such vintage filters. This presents an oppor- tunity to revisit the real photographic processes that produce the looks they copy and to explore their potential for creat- ing novel digital experiences and image editing tools; this is something currently neglected with the reduced selection of canned effects and textures available to the digital artist. The resulting interaction metaphors seek to bring back the craftsmanship and exploratory approach to image creation of those analog alternative photographic processes [Jam09], such as wet plate collodion or printmaking (as seen in Fig- ure 2), noticeably lost in the transition from analog to digital photography. Currently kept alive by professionals and afi- cionados, they allow for a wide range of impressive tonal and emotional variations. Some are intended and carefully chosen, such as the exact composition of the chemicals in- volved; some arise serendipitously due to imperfections and the manual manipulation of liquid solutions; and some are due to the individual skills and particular methodology of each practitioner. We present a novel computational framework for physi- c 2013 The Author(s) Computer Graphics Forum c 2013 The Eurographics Association and Blackwell Publish- ing Ltd. Published by Blackwell Publishing, 9600 Garsington Road, Oxford OX4 2DQ, UK and 350 Main Street, Malden, MA 02148, USA.