ECHO — Layer Mastery: The Power of Masks
Source photo sets (v2), credits, and sourcing notes
====================================================

Every set below is ONE subject (or one crew) at ONE event/session, captured in
multiple genuinely different moments, under consistent lighting color. Every file
was downloaded and opened before inclusion — no set here rests on a search caption.

Pexels free license: attribution not legally required, but photographer credit is
good practice beyond classroom use.


SET A — GOLDEN HOUR  (strongest set; use this one for the demo)
  Hero_skater_midair_grab.jpg       https://www.pexels.com/photo/33642193/
  Secondary_skater_bowl_edge.jpg    https://www.pexels.com/photo/33642191/
  Optional_third_skater_airborne.jpg https://www.pexels.com/photo/33642181/

  Venice Beach Skatepark, Los Angeles. Same skater (white tee, dark pants),
  same bowl, same sunset session, three clearly different moments: a close
  mid-air grab, an approach at the bowl edge, and a wide airborne seat grab.
  ALL THREE ARE PORTRAIT (1600x2400) — no reframing needed.
  Color is warm gold/peach throughout; measured average RGB across the three
  frames sits within a narrow range, the tightest color match of any set here.


SET B — CONCERT NIGHT  (blue-lit subset)
  Hero_singer_fullbody_blue.jpg        https://www.pexels.com/photo/16106057/
  Secondary_singer_closeup_blue.jpg    https://www.pexels.com/photo/16106341/
  Optional_third_singer_wide_blue.jpg  https://www.pexels.com/photo/16106035/

  Same performer, same outfit, same show, three different moments.
  This replaces the earlier version of this set, which mixed blue, yellow and
  multicolored stage lighting. The contributor's gallery has nine frames; these
  are the three that are blue-dominant, so the set now reads as one lighting
  state instead of three. The remaining warm/mixed frames were deliberately left
  out for that reason.
  Hero is portrait; the other two are landscape and need the reframing move
  described in the walkthrough.
  Note: this set features a real, identifiable performer's face across all three
  images. Fine under the Pexels license, but a different thing from an anonymous
  stock subject — worth knowing before it goes to a class.


SET C — TRACK DAY  (supplied by Chase, not sourced in this session)
  Hero_runner_starting_crouch.jpg       pexels-mikhail-nilov-8454953
  Secondary_runner_midstride.jpg        pexels-mikhail-nilov-8454926
  Optional_third_runner_resting.jpg     pexels-mikhail-nilov-8455333
  Alternate_runner_crouch_sideview.jpg  pexels-mikhail-nilov-8454952

  Photographer: Mikhail Nilov (Pexels).
  One runner, one outfit, one track, one overcast session. Three moments in a
  natural order: starting crouch, mid-stride, resting afterward. The fourth file
  is a side-angle version of the crouch, offered as an alternate Hero.
  All four are portrait. Originals ran 4000-6000px on the long edge, far heavier
  than a 1200x1500 canvas needs, so they are resized here to 2400px tall.
  Measured color across the four sits in a tight warm range (red track plus navy
  jacket under flat daylight), comparable to Set A.
  This set replaced an earlier black-and-white skate-crew set, which had two
  weaknesses this one does not: different individuals were the main subject in
  different frames, and all its frames were landscape.
  Note: features a real, identifiable person's face across all frames, same
  consideration as Set B.

SET D — SPOTLIGHT  (ballet; lead supplied by Chase)
  Hero_ballerina_arabesque.jpg           https://www.pexels.com/photo/8462796/
  Secondary_ballerina_portrait.jpg       https://www.pexels.com/photo/8462771/
  Optional_third_ballerina_full_stage.jpg https://www.pexels.com/photo/8463028/
  Alternate_ballerina_dancing.jpg        https://www.pexels.com/photo/8462767/

  Photographer: MART PRODUCTION (Pexels).
  One dancer, one white tutu, one spotlit session on a dark stage. Three
  different moments AND three different scales, which is exactly what the blend
  step wants: a big dramatic arabesque, a tight shoulders-and-face portrait, and
  a wide full-stage shot with the figure small in frame.
  All portrait. Measured color is near-neutral on every frame (red, green and
  blue channel averages within a few points of each other), so this is the
  tightest color match of any set here — effectively monochrome without being
  black and white.
  The contributor's shoot has at least 13 usable frames. Four are included; the
  rest sit at pexels.com/@mart-production if more variety is ever wanted.
  Brightness note: the shoot splits into a very dark tier and a lighter tier.
  All four files here are from the dark tier so they match; mixing tiers would
  reintroduce the inconsistency this set was chosen to avoid.
  CAVEAT: the tutu is sheer. Quick Selection handles solid edges well but
  struggles where the black background reads through the tulle. This matters
  less than it sounds, because the composite background is also near-black, so
  a rough skirt edge mostly disappears. Still, this is the one set where the
  selection step needs patience — Set A or C is the safer demo.

HOW THESE WERE FOUND (worth repeating; generic keyword search does not work)
  Pexels assigns tightly clustered IDs to frames uploaded together from one
  shoot. Finding one good photo and scanning nearby IDs surfaces its siblings.
  That is how Sets A and C were found. Caveat: this only holds for recent,
  high-numbered IDs. Low IDs (five digits, from the site's early years) are
  ordered by upload date across a contributor's whole portfolio, so neighboring
  numbers there are unrelated photos — that trap is what killed one candidate
  set during this search.


RULED OUT AFTER TESTING (recorded so these are not re-attempted)
  Wedding photography — full same-day coverage is photographers' paid work and
    is not released to free stock libraries.
  Marathon/race day — same structure; bib-searchable race photos are a
    commercial delivery industry, not free stock.
  Ballet/dance studio, two attempts — generic search returns unrelated single
    photos. The one same-photographer pair found (Sarah Pflug, Burst) turned out
    to be different costumes and different processing: two sessions, not one.
  Surfers at golden hour — color consistency is excellent, but subjects are
    distant silhouettes in water, unusable for cutting out and masking.
  Early-ID skate gallery (IDs 10629-10635) — consecutive IDs from one
    contributor, but spanning unrelated old uploads (one was a lime in a drink).

  Two earlier candidates were also dropped for caption/photo mismatch:
  pexels.com/photo/2828634 (described as a guitarist, actually a seated figure
  with no guitar) and pexels.com/photo/4766712 (described as a dancer, actually
  a person carrying a bodyboard).
